w p 


CROSS-SECTIONAL    DIAGRAM    OF 

78  I 


1— Divided  front  seat  for  chauffeur. 

2— Throttle  lever. 

3— Steering  wheel. 

4— Steering  pillar. 

5— Brake  or  clutch  lever. 

6— Spark  coil. 

7— Spark  coil  vibrator. 

8— Gravity  feed  gasolene  tank. 

9— Water  jacket  wall. 
10— Cylinder  wall. 
11— Piston. 
13— Piston  ring. 
13— Compression  chamber. 
14— Inlet  valve. 
1&— Spark  plug. 
18— Relief  cock. 
17— Exhaust  valy*. 


68  6?   66 


18-Mixer. 

19— Intake  pipe. 

30 — Exhaust  pipe. 

21 — Engine  Bonnet. 

22— Water  circulating  pipe. 

23— Water  circulating  pipe. 

24 — Oil  pump  gear. 

25 — Radiator  cap. 

26— Water  tank. 

27— Radiator. 

28— Air  Cooling  fan. 

29— Driving  chain  for  fan. 

30— Starting  crank. 

31— Water  pump. 

32— Forward  spring  support. 

33— Commutator. 

34— Forward  spring. 


36— Tubular  fro 

36— Spoke. 
37— Felloe. 
38— Rim. 
39— Pneumatic ' 
40— Oil  governo 
41— Tubular  sut 
42— Oil  governo: 
43— Reserve  oil 
44— Parallel  rod 
45— Steering  roc 
46— Cam     actui 

valve. 

47— Cam  actuat 
48— Sliding  beai 
49— Connecting 
50— Connecting 


AMERICAN    FOUR-CYLINDER    TOURING    CAR. 


42    41  40 


ile. 


tnatlng  pump, 
me  of  engine, 
ton. 
iber. 


:     the    exhaust 

he  inlet  valve, 
for  cam  shaft, 
and. 


51-  Crank. 

53 — Crank  shaft  of  engine. 

53— Fly-wheel. 

64 — Expansion  clutch. 

56— Ball   bearing   for  transmission 

shaft. 

56 — Planetary  transmission. 
57 — Transmission  brake  drum. 
58— Universal  joint. 
59— Exhaust  pipe. 
60-Brake  rod. 

61— Pressure  feed  pipe  for  gasolene. 
62— Driving  shaft. 
63— Muffler. 
64— Universal  joint. 
65 — Rear  side  spring. 
66 — Bevel  gear  driving  pinion. 


67— Differential  pinion  stud. 

68 — Differential  pinion. 

69 — Differential  housing. 

70— Main  gasolene  tank. 

71— Rear  spring  support. 

72— Pressed  steel  side  frame. 

73— Swinging     filler    for     gasolc 

tank. 

74— Wooden  frame  of  body. 
75 — Upholstering. 
76 — Upholstering  spring. 
77— Aluminum  body. 
78— Tonneau. 
79— Side  entrance  door. 


SELF-PROPELLED  VEHICLES 


A    PRACTICAL    TREATISE 

ON    THE 

THEORY,    CONSTRUCTION,     OPERATION, 
CARE    AND    MANAGEMENT 

OF   AI,!,    FORMS    OF 

AUTOMOBILES 


JAMES  E.  HOMANS,  A.  M. 


WITH  UPWARDS  OF  500  ILLUSTRATIONS  AND  DIAGRAMS, 
GIVING  THE  ESSENTIAL  DETAILS  OF  CONSTRUCTION 
AND  MANY  IMPORTANT  POINTS  ON  THE  SUCCESSFUL 
OPERATION  OF  THE  VARIOUS  TYPES  OK  MOTOR  CAR- 
RIAGES DRIVEN  BY  STEAM,  GASOLINE  AND  ELECTRICITY, 


THEO.    AUDEIv    &    COMPANY 

SEVRXTY-TWO    FIFTH    AVENUE 
NEW    YORK 

I9H 


ALL    RIGHTS    RESERVED. 


-Copyright  1902.  1904.  1906  and  1909  by 


THEO.  AUDEL  &  CO.,  NEW  YORK. 
Entered  at  Stationers  Hall,  London,  England. 

Protected  by  International  Copyright  in  Great  Britain, 

and  all  her  Colonies,  and,  under  the  provisions 

of  the  Berne  Convention,  in 

Belgium,  France,  Germany,   Italy,   Spain,   Switzerland, 

Tunis,   Hayti,  Luxembourg,  Monaco. 

Montenegro  and  Norway. 


NOTIFICATION 

UCunui  all  iTlrtt  In;  lijrnr 

Parties  desiring  to  make  any  undue  use  of  any  part 
of  this  publication  are  hereby  formally  requested  to 
communicate  with  the  Publishers. 

Failing  in  this  respect  it  will  not  only  be  considered 
discourteous,  but  an  infringement  of  the  International 
Copyright  and  Common  Law. 

THE  PUBLISHERS. 


Printed  in  the  United  States. 


GOTTLIEB    DAIMLER 

(1834-1899) 

INVENTOR  OF  THE  PRACTICAL  HIGH-SPEED  GASOLINE  MOTOR 
AND 

"FATHER  OF  THE  AUTOMOBILE" 


PREFACE. 


Since  the  publication  of  the  first  edition  of  this  book  the 
motor  vehicle  has  passed  out  of  the  experimental  stage  and 
become  a  practical  reality.  That  it  is  now  a  permanent  factor 
in  the  world  of  mechanics,  in  the  domain  of  travel  and  recrea- 
tion, and,  latterly  also,  in  commercial  life,  cannot  for  a  moment 
be  questioned.  Already  the  profession  of  chauffeur,  or 
automobile  driver,  has  taken  rank  among  skilled  callings, 
affording  a  new  and  profitable  field  of  effort.  The  demand 
for  information  of  a  practical  character  is  insistent.  This  de- 
mand the  present  revised  edition  attempts  to  meet. 

The  motor  vehicle  is  a  singularly  complex  machine.  Its 
construction  and  operation  involve  the  consideration  of  an  ex- 
tensive range  of  facts  in  several  widely  separated  departments 
of  mechanical  knowledge.  The  study  of  its  construction  and 
operation  is  a  liberal  education  in  itself.  It  claims  a  broad 
territory. 

In  order  to  answer  every  question  that  must  occur  to  the 
practical  automobilist,  one  must  produce  a  whole  library  of 
books,  rather  than  a  single  volume  of  convenient  size.  Virtu- 
ally all  such  questions  may  be  forestalled,  however,  by  clear 
explanations  of  the  principles  governing  the  design  and  con- 
struction of  the  machine,  and  the  most  conspicuous  situations 
involved  in  its  operation.  It  must  be  said,  to  the  credit  of 
both  designer  and  operator,  that  questions,  perplexities  and 
accidents  are  far  fewer  at  the  present  time  than  several  years 


PREFACE. 

ago.  This  is  due  to  the  general  dissemination  of  knowledge 
of  a  practical  character,  also  to  the  fact  that  the  public  has 
learned  to  consider  the  motor  vehicle  seriously,  and  award  it 
the  attention  it  deserves. 

To  the  vast  realm  of  motordom  the  present  volume  essays 
to  discharge  the  function  of  a  general  introduction ;  a  con- 
venient guide  book  to  the  intricacies  that  must  inevitably  be 
encountered ;  a  summary  of  the  facts  and  principles  that  it  is 
necessary  to  understand.  As  far  as  possible,  the  presentation 
of  subjects  has  been  determined  by  consideration  of  the  needs 
of  the  man  behind  the  wheel.  Irrelevant  matters  have  been 
eliminated,  and  attention  has  been  guided  toward  present  con- 
ditions, to  the  exclusion  of  all  that  is  experimental  and 
obsolete. 

Honest  criticism  and  suggestions  would  be  genuinely  appre- 
ciated by  both  the  author  and  the  publishers,  who  would  es- 
teem it  an  assistance  in  the  direction  of  adequately  dealing 
with  a  subject  that  is  of  great  interest  and  still  greater  impor- 
tance at  the  present  time. 

For  kind  assistance  in  the  preparation  of  this  new  edition 
the  author  begs  to  render  thanks  to  Mr.  Charles  E.  Duryea  ; 
to  Mr.  E.  W.  Wright ;  to  several  leading  authorities  and 
manufacturers  who  have  cheerfully  furnished  information,  as 
acknowledged  in  the  text ;  to  a  number  of  readers  of  older 
editions,  who  have  made  intelligent  suggestions,  and  asked 
even  more  suggestive  questions ;  and  to  the  reading  public, 
whose  generous  appreciation  has  encouraged  him  to  attempt 
improvement  on  his  former  efforts. 


TABLE   OF  CONTENTS. 

CHAPTER.  PAOB. 

I. — BRIEF  HISTORY  OP  SELF-PROPELLED  VEHICLES 1-12 

II. — THE  MAKE-UP  OF  A  MOTOR  CARRIAGE 13-15 

III. — COMPENSATION  AND  COMPENSATING  DEVICES 16-22 

IV. — THE  DRIVING  GEAR 23-41 

V. — THE  STEERING  OF  A  MOTOR  VEHICLE 42-62 

VI. — COMBINED  STEERING  AND  DRIVING 63-66 

VII. — THE  SUPPORTS  OF  A  MOTOR  VEHICLE 67-88 

VIII. — MOTOR  CARRIAGE  WHEELS 89-98 

IX. — SOLID   RUBBER  TIRES;    THEIR  THEORY  AND  CON- 
STRUCTION    99-106 

X. — THE  CONSTRUCTION  AND  TYPES  OF  PNEUMATIC  TIRES  107-118 

XI. — PNEUMATIC  TIRE  TROUBLES 1 19-125 

XII. — CARE  OF  PNEUMATIC  TIRES 126-131 

XIII. — TYPES  AND  MERITS  OF  AUTOMOBILES 132-135 

XIV. — THE  THEORY  OF  HEAT  ENGINES 136-148 

XV. — THE  PARTS  OF  A  GAS  ENGINE H9-I53 

XVI. — THE  FOUR  CYCLE  GAS  ENGINE 154-157 

XVII.— THE  Two  CYCLE  GAS  ENGINE 158-162 

XVIII. — THE  CONDITIONS  OF  COMPRESSION  AND  EXPANSION..  163-169 

XIX. — OPERATION  AND  EFFICIENCY  IN  A  GAS  ENGINE 170-174 

XX. — THE  EXHAUST  OF  A  GAS  ENGINE 175-182 

XXI. — WATER-COOLING  FOR  THE  CYLINDER 183-190 

XXII. AIR-COOLING  FOR  THE  CYLINDER 191-196 

XXIII. — POWER  ELEMENTS  OF  A  GAS  ENGINE 197-204 


TABLE    OF     CONTENTS. 

CHAPTER.  PAGS. 

XXIV. — CARBURETTERS  AND  CARBURETTING 205-254 

XXV. — IGNITION 255-322 

XXVI. — BALANCING  GASOLINE  ENGINES 323-339 

XXVII. — GOVERNING  AND  CONTROL  OF  A  GASOLINE  ENGINE  . . .  340-354 

XXVIII. — CLUTCHES  AND  TR,  NSMISSIONS 355-366 

XXIX. — TRANSMISSIONS 367-393 

XXX. — ON  THE  CONSTRUCTION  AND  OPERATION  OP  BRAKES 

ON  MOTOR  CARRIAGES 394-400 

XXXI. — ON  BALL  AND  ROLLER  BEARINGS  FOR  MOTOR  CAR- 
RIAGE USE 401-406 

XXXII. — ON  THE  NATURE  AND  USE  OF  LUBRICANTS 407-414 

XXXIII. — PRACTICAL  OPERATION  OF  GASOLINE  ENGINES 415-450 

XXXIV.— MOTOR  CYCLES 451-466 

XXXV. — THE  OPERATION  AND  CONSTRUCTION  OF  STEAM  EN- 
GINES FOR  AUTOMOBILES 467-484 

XXXVI. — BOILERS  AND  FLASH  GENERATORS 485-50-2 

XXXVII. — LIQUID  FUEL  BURNERS  AND  REGULATORS 503-5 12 

XXXVIII. — BOILER  ATTACHMENTS  AND  AUTOMATIC  REGULATING 

DEVICES 513-522 

XXXIX. — STEAM  SYSTEMS 523-554 

XL. — ELECTRIC  VEHICLES 555-558 

XLI. — PRINCIPLES  OP  ELECTRICITY 559-564 

XLII. — THE  OPERATION  AND  CONSTRUCTION  OP  DYNAMOS 

AND  MOTORS 565-574 

XLIII. — STORAGE  BATTERIES 575*594 

XLIV. — METHODS    OF    CIRCUIT    CHANGING    IN    ELECTRICAL 

MOTOR  VEHICLES,  AND  THEIR  OPERATIONS 595-608 

XLV. — AUTOMOBILE  RUNNING,  CARE  AND  REPAIR 609-645 

READY  REFERENCE  INDEX. 


CHAPTER  ONE. 

A  BRIEF  HISTORY   OF  SELF-PROPELLED   ROAD  VEHICLES. 

Requirements  for  a  Successful  flotor  Carriage. — Even 
before  the  days  of  successful  railroad  locomotives  several  in- 
ventors had  proposed  to  themselves  the  problem  of  a  steam- 
propelled  road  wagon,  and  actually  made  attempts  to  build  ma- 
chines to  embody  their  designs.  In  1769  Nicholas  Joseph 
Cugnot,  a  captain  in  the  French  army,  constructed  a  three- 
wheeled  wagon,  having  the  boiler  and  engine  overhanging,  and 
to  be  turned  with  the  forward  wheel,  and  propelled  by  a  pair  of 
single-acting  cylinders,  which  worked  on  ratchets  geared  to  the 
axle  shaft.  It  was  immensely  heavy,  awkward  and  unmanageable, 
but  succeeded  in  making  the  rather  unexpected  record  of  two  and 
a  half  miles  per  hour,  over  the  wretched  roads  of  that  day,  despite 
the  fact  that  it  must  stop  every  few  hundred  feet  to  steam  up.  Later 
attempts  in  the  same  direction  introduced  several  of  the  essential 
motor  vehicle  parts  used  at  the  present  day,  and  with  commen- 
surately  good  results.  But  the  really  practical  road  carriage  can- 
not be  said  to  have  existed  until  inventors  grasped  the  idea  that 
the  fuel  for  the  engines  must  be  something  other  than  coal,  and 
that,  so  far  as  the  boilers  and  driving  gears  are  concerned,  the 
minimum  of  lightness  and  compactness  must  somehow  be  com- 
bined with  the  maximum  of  power  and  speed.  This  seems  a  very 
simple  problem,  but  we  must  recollect  that  even  the  simplest 
results  are  often  the  hardest  to  attain.  Just  as  the  art  of  printing 
dates  from  the  invention  of  an  inexpensive  method  of  making 
paper,  so  light  vehicle  motors  were  first  made  possible  by  the 
successful  production  of  liquid  or  volatile  fuels. 

In  addition  to  this,  as  we  shall  presently  understand,  immense 
contributions  to  the  present  successful  issue  have  been  made  by 
pneumatic  tires,  stud  steering  axles  and  balance  gears,  none  of 
which  were  used  in  the  motor  carriages  of  sixty  and  eighty  years 
ago.  So  that,  we  may  confidently  insist,  although  many  thought- 
less persons  still  assert  that  the  motor  carriage  industry  is  in  its 
infancy,  and  its  results  tentative,  we  have  already  most  of  the 


2  SELF-PROPELLED    VEHICLES. 

elements  of  the  perfect  machine,  and  approximations  of  the  re- 
mainder. At  the  present  time  the  problem  is  not  on  what  ma- 
chine can  do  the  required  work,  but  which  one  can  do  it  best. 

A  Brief  Review  of  Motor  Carriage  History — As  might  be 
readily  surmised,  the  earliest  motor  vehicles  were  those  propelled 
by  steam  engines,  the  first  attempt,  that  of  Capt.  Cugnot,  dating, 
as  we  have  seen,  from  1769-70.  In  the  early  years  of  the , nine- 
teenth century,  and  until  about  1840-45,  a  large  number  of  steam 


FIG.  1 — Captain  Cugnot 'a  Three-wheel  Steam  Artillery  Carriage  (1769-70).    This  cut  shows 
details  of  the  single  flue  boiler  and  of  the  driving  connections. 

carriages  and  stage  coaches  were  designed  and  built  in  England, 
some  of  them  enjoying  considerable  success  and  bringing  profit 
to  their  owners.  At  about  the  close  of  this  period,  however,  strict 
laws  regarding  the  reservation  of  highways  to  horse-vehicles  put 
an  effectual  stop  to  the  further  progress  of  an  industry  that  was 
already  well  on  its  way  to  perfection,  and  for  over  forty  years 
little  was  done,  either  in  Europe  or  America,  beyond  improving 
the  type  of  farm  tractors  and  steam  road  rollers,  with  one  or  two 
sporadic  attempts  to  introduce  self-propelling  steam  fire  engines. 
During  the  whole  of  this  period  the  light  steam  road  carriage 
existed  only  as  a  pet  hobby  of  ambitious  inventors,  or  as  a  curi- 
osity for  exhibition  purposes.  Curiously  enough,  while  the 
progress  of  railroad  locomotion  was,  in  the  meantime,  rapid  and 
brilliant,  the  re-awakening  of  the  motor  carriage  idea  and  in- 
dustry, about  1885-89,  was  really  the  birth  of  a  new  science  of 
constructions,  very  few  of  the  features  of  former  carriages  being 
then  adopted.  In  1885  Gottlieb  Daimler  patented  his  high-speed 
gas  or  mineral  spirit  engine,  the  parent  and  prototype  of  the  wide 


MOTOR    VEHICLE  HISTORY.  3 

variety  of  explosive  vehicle  motors  since  produced  and,  in  the 
same  year,  Carl  Benz,  of  Mannheim,  constructed  and  patented 
his  first  gasoline  tricycles.  The  next  period  of  progress,  in  the 
years  immediately  succeeding,  saw  the  ascendency  of  French 
engineers,  Peugeot,  Panhard,  De  Dion  and  Mors,  whose 
names,  next  to  that  of  Daimler  himself,  have  become  common- 
places with  all  who  speak  of  motor  carriages.  In  1889  Leon 
Serpollet,  of  Paris,  invented  his  famous  instantaneous,  or  "flash," 
generator,  which  was,  fairly  enough,  the  most  potent  agent  in 
restoring  the  steam  engine  to  consideration  as  means  of  motor 


Fio.  £  — Richard  Trevithick's  Steam  Road  Carriage  (1802).  The  centre-pivoted  front 
axle  is  about  half  the  length  of  the  rear  axle.  The  cylinder  is  fixed  in  the  centre  of 
the  boiler.  The  engine  has  a  fly-wheel  and  spur  gear  connections  to  the  drive  axle. 

carriage  propulsion.  Although  it  has  not  become  the  prevailing 
type  of  steam  generator  for  this  purpose,  it  did  much  to  turn  the 
attention  of  engineers  to  the  work  of  designing  high-power, 
quick-steaming,  small-sized  boilers,  which  have  been  brought  to 
such  high  efficiency,  particularly  in  the  United  States.  With 
perfected  steam  generators  came  also  the  various  forms  of  liquid 
or  gas  fuel  burners.  The  successful  electric  carriage  dates  from 
a  few  years  later  than  either  of  the  others,  making  its  appearance 
as  a  practical  permanency  about  1893-94. 

Trevithick's  Steam  Carriage. — In  reviewing  the  history  of 
motor  road  vehicles  we  will  discover  the  fact  that  the  attempts 
which  were  never  more  than  plans  on  paper,  working  models,  or 
downright  failures  are  greatly  in  excess  of  the  ones  even  half- 


4  SELF-PROPELLED    VEHICLES. 

way  practical.  From  within  a  few  years  after  Cugnot's  notable 
attempt  and  failure,  many  inventors  in  England,  France  and 
America  appeared  as  sponsors  for  some  kind  of  a  steam  road  car- 
riage, and  as  invariably  contributed  little  to  the  practical  solution 
of  the  problem.  In  1802  Richard  Trevithick,  an  engineer  of  abil- 
ity, subsequently  active  in  the  work  of  developing  railroad  cars 
and  locomotives,  built  a  steam-propelled  road  carriage,  which, 
if  we  may  judge  from  the  drawings  and  plans  still  extant,  was 
altogether  unique,  both  in  design  and  operation.  The  body  was 
supported  fully  six  feet  from  the  ground,  above  rear  driving 
wheels  of  from  eight  to  ten  feet  in  diameter,  which,  turning  loose 
on  the  axle  trees,  were  propelled  by  spur  gears  secured  to  the 
hubs.  The  cylinder  placed  in  the  centre  of  the  boiler  turned  its 
crank  on  the  counter-shaft,  just  forward  of  the  axle,  and  imparted 
its  motion  through  a  second  pair  of  spur  gears,  meshing  with 
those  attached  to  the  wheel  hubs.  The  steering  was  by  the  for- 
ward wheels,  whose  axle  was  about  half  the  width  of  the  vehicle, 
and  centre-pivoted,  so  as  to  be  actuated  by  a  hand  lever  rising 
in  front  of  the  driver's  seat.  This  difference  in  the  length  of  the 
two  axles  was  probably  a  great  advantage  to  positive  steering 
qualities,  even  in  the  absence  of  any  kind  of  compensating  device 
on  the  drive  shaft.  The  carriage  was  a  failure,  however,  owing 
to  lack  of  financial  support,  as  is  alleged,  and,  after  a  few  trial 
runs  about  London,  was  finally  dismantled. 

Gurney's  Coaches.— lThe  Golden  Age  of  steam  coaches  ex- 
tended from  the  early  twenties  of  the  nineteenth  century  for  about 
twenty  years.  During  this  period  much  was  done  to  demonstrate 
the  practicability  of  steam  road  carriages,  which  for  a  time 
seemed  promising  rivals  to  the  budding  railroad  industry.  Con- 
siderable capital  was  invested  and  a  number  of  carriages  were 
built,  which  actually  carried  thousands  of  passengers  over  the  old 
stage-coach  roads,  until  adverse  legislation  set  an  abrupt  period 
to  further  extension  of  the  enterprise.  Among  the  names  made 
prominent  in  these  years  is  that  of  Goldsworthy  Gurney,  who,  in 
association  with  a  certain  Sir  Charles  Dance,  also  an  engineer, 
constructed  several  coaches,  which  enjoyed  a  brief  though  suc- 
cessful career.  His  boiler,  like  those  then  used  in  the  majority 
of  carriages,  was  of  the  water-tube  variety,  and  in  many  respects 


MOTOR    VEHICLE  HISTORY.  5 

closely  resembled  some  of  the  most  successful  styles  made  at  the 
present  day.  It  consisted  of  two  parallel  horizontal  cylindrical 
drums,  set  one  above  the  other  in  the  width  of  the  carriage,  sur- 
mounted by  a  third,  a  separator  tube,  and  connected  together 
by  a  number  of  tubes,  each  shaped  like  the  letter  U  laid  on  its 
side,  and  also,  directly,  by  several  vertical  tubes.  The  fire  was 
applied  to  the  lower  sides  of  the  bent  tubes,  under  forced  draught, 
thus  creating  a  circulation,  but,  on  account  of  the  small  heating 
surface,  the  boiler  was  largely  a  failure.  Mr,  Dance  did  much 

A 


3. — Sectional  Elevation  of  one  of  Goldsworthy  Qurney's  Early  Coaches,  showing 
water  tube  boiler,  directly  geared  cylinders  and  peg-rod  driving  wheel. 

to  remedy  the  defects  of  Gurney's  boiler  with  a  water-tube  gen- 
erator, designed  by  himself,  in  which  the  triple  rows  of  parallel 
U-tubes  were  replaced  by  a  number  of  similarly-shaped  tubes 
connected  around  a  common  circumference  by  elbow  joints,  and 
surmounted  by  dry  steam  tubes,  thus  affording  a  much  larger 
heating  surface  for  the  fire  kindled  above  the  lower  sides  of  the 
bent  tubes.  Gurney's  engine  consisted  of  two  parallel  cylinders, 
fixed  in  the  length  of  the  carriage  and  operating  cranks  on  the 
revolving  rear  axle  shaft.  The  wheels  turned  loose  on  the  axles, 
and  were  driven  by  double  arms  extending  in  both  directions 


SELF-PROPELLED    VEHICLES. 


from  the  axle  to  the  felloe  of  the  wheel,  where  they  engaged  suit- 
ably arranged  bolts,  or  plugs.  On  level  roadways  only  one  wheel 
was  driven,  in  order  to  allow  of  turning,  but  in  ascending  hills 
both  were  geared  to  the  motor,  thus  giving  full  power.  In  Gur- 
ney's  later  coaches  and  tractors  the  steering  was  by  a  sector, 


FIG.  4.  Fio.  5. 

FIGS.    -W.  —Improved  Boilers  for  Gurney  Coaches  ;  the  first  by  Summers  &  Ogle ;  the 
second  by  Maceroni  &  Squire. 

with  its  centre  on  the  pivot  of  the  swinging  axle  shaft  and  oper- 
ated by  a  gear  wheel  at  the  end  of  the  revolving  steering  post.  In 
one  of  his  earliest  carriages  he  attempted  the  result  with  an  extra 
wheel  forward  of  the  body  and  the  four-wheel  running  frame, 
the  swinging  forward  axle  being  omitted,  but  this  arrangement 
speedily  proving  useless,  was  abandoned. 

Improvements  on  Qurney's  Ccaches. — Several  other  builders, 
notably  Maceroni  and  Squire,  and  Summers  and  Ogle,  adopted 
the  general  plans  of  Gurney's  coaches  and  driving  gear,  but 
added  improvements  of  their  own  in  the  construction  of  the 
boilers  and  running  gear.  The  former  partners  used  a  water- 
tube  boiler  consisting  of  eighty  vertical  tubes,  all  but  eighteen 
of  which  were  connected  at  top  and  bottom  by  elbows  or  stay- 
tubes,  the  others  being  extended  so  as  to  communicate  with  a 


MOTOR    VEHICLE  HISTORY.  7 

central  vertical  steam  drum.  Summers  and  Ogle's  boiler  con- 
sisted of  thirty  combined  water  tubes  and  smoke  flues,  fitting 
into  square  plan,  flat  vertical-axis  drums  at  top  and  bottom.  Into 
each  of  these  drums — the  one  for  water,  the  other  for  steam — the 
water  tubes  opened,  while  through  the  top  and  bottom  plates, 
through  the  length  of  the  water-tubes,  ran  the  contained  smoke 
flues,  leading  the  products  of  combustion  upward  from  the  fur- 
nace. The  advantage  of  this  construction  was  that  considerable 
water  could  be  thus  heated,  under  draught,  in  small  tube  sec- 
tions, while  the  full  effect  of  250  square  feet  of  heating  surface 
was  realized.  With  both  these  boilers  exceedingly  good  results 
were  obtained,  both  in  efficiency  and  in  small  cost  of  operation. 
Indeed,  the  reasonable  cost  of  running  these  old-time  steam  car- 
riages is  surprising.  It  has  been  stated  that  Gurney  and  Dance's 
coaches  required  on  an  average  about  4d.  (eight  cents)  per  mile 
for  fuel  coke,  while  the  coaches  built  by  Maceroni  and  Squire 
often  averaged  as  low  as  3d.  (six  cents).  The  average  weight  of 
the  eight  and  ten-passenger  coaches  was  nearly  5,000  pounds, 
their  speed,  between  ten  and  thirty  miles,  and  the  steam  pressure 
used  about  200  pounds. 

Hancock's  Coaches. — By  all  odds  the  most  brilliant  record 
among  the  early  builders  of  steam  road  carriages  is  that  of  Walter 
Hancock,  who,  between  the  years  1828  and  1838,  built  nine  car- 
riages, six  of  them  having  seen  actual  use  in  the  work  of  carrying 
passengers.  His  first  effort,  a  three-wheeled  phaeton,  was  driven 
by  a  pair  of  oscillating  cylinders  geared  direct  to  the  front  wheel, 
and  being  turned  on  the  frame  with  it  in  steering.  Having 
learned  by  actual  experiment  the  faults  of  this  construction,  he 
adopted  the  most  approved  practice  of  driving  on  the  rear  axle, 
and  in  his  first  passenger  coach,  "The  Infant,"  he  attached  his 
oscillating  cylinder  at  the  rear  of  the  frame,  and  transmitted  the 
power  by  an  ordinary  flat-link  chain  to  the  rotating  axle.  He 
was  the  first  to  use  the  chain  transmission. 

As  Hancock  seems  to  have  been  a  person  who  readily  learned 
by  experience,  he  soon  saw  that  the  exposure  of  his  engines  to 
dust  and  other  abradents  was  a  great  source  of  wear  and  disable- 
ment ;  consequently  in  his  second  coach,  "Infant  No.  2,"  he  sup- 
planted the  oscillating  cylinder  hung  outside  by  a  slide-valve 


8 


SELF-PROPELLED    VEHICLES. 


cylinder  and  crank  disposed  within  the  rear  of  the  coach  body 
above  the  floor.  In  this  and  subsequent  carriages  he  used  the 
chain  drive,  also  operating  the  boiler  feed  pump  from  the  cross- 
head,  as  in  most  steam  carriages  at  the  present  day. 

Hancock's  boiler  was  certainly  the  most  interesting  feature  of 
his  carriages,  both  in  point  of  original  conception  and  efficiency 
in  steaming.  It  was  composed  of  a  number  of  flat  chambers — 
"water  bags"  they  were  called — laid  side  by  side  and  intercom- 
municating with  a  water  drum  at  the  base -and  steam  drum  at 
the  top.  Each  of  these  chambers  was  constructed  from  a  flat 
sheet  of  metal,  hammered  into  the  required  shape  and  flanged 
along  the  edges,  and,  being  folded  together  at  the  middle  point, 


FIG.  8.— Part  section  of  one  of  Hancock's  Coaches,  showing  Engine  and  Driving  Connec- 
tions. A  is  the  exhaust  pipe  leading  steam  against  the  screen,  C,  thence  up  the  flue, 
D,  along  with  smoke  and  gases  from  the  grate,  B.  E  is  the  boiler;  H  the  o'ut-take 
pipe;  K  the  engine  cylinder  and,  J,  the  water-feed  pump;  G  is  a  rotary  fan  for  produc- 
ing a  forced  draught,  and  F  the  flue  leading  it  to  the  grate. 

the  two  halves  were  securely  riveted  together  through  the 
flanged  edge.  The  faces  of  each  plate  carried  regularly  disposed 
hemispherical  cavities  or  bosses,  which  were  in  contact  when  the 
plates  were  laid  together,  thus  preserving  the  distances  between 
them  and  allowing  space  for  the  gases  of  combustion  to  pass  over 
an  extended  heating  surface.  The  high  quality  of  this  style  of 
generator  may  be  understood  when  we  learn  that,  with  eleven 
such  chambers  or  "water  bags,"  30  x  20  inches  x  2  inches  in 
thickness  and  89  square  feet  of  heating  surface  to  6  square  feet 
of  grate,  one  effective  horse-power  to  every  five  square  feet  was 


MOTOR    VEHICLE  HISTORY. 


realized,  which  gives  us  about  eighteen  effective  horse-power 
for  a  generator  occupying  about  n.i  cubic  feet  of  space,  or  30  x 
20  x  32  inches. 

The  operation  of  the  Hancock  boiler  is  interesting.  The  most 
approved  construction  was  to  place  the  grate  slightly  to  the  rear 
of  the  boiler's  centre,  and  the  fuel,  coke,  was  burnt  under  forced 
draught  from  a  rotary  fan.  The  exhaust  steam  was  forced  into 
the  space  below  the  boiler,  where  a  good  part  of  it,  passing 
through  a  finely  perforated  screen,  was  transformed  into  water 
gas,  greatly  to  the  benefit  of  perfect  combustion. 


\ 


FIG.  T. 


FIG  8. 


FIG.   7.— Hancock's  Wedge  Drive  Wheel,  showing  wedge  spokes  and  triangular  driving 

lugs  at  the  nave. 
Fio.    S.— One  element  of  the  Hancock  Boiler,  end  view. 

As  early  as  1830  Hancock  devised  the  "wedge"  wheels,  since 
so  widely  adopted  as  models  of  construction.  As  shown  in  the 
accompanying  diagram,  his  spokes  were  formed,  each  with  a 
blunt  wedge  at  its  end,  tapering  on  two  radii  from  the  nave  of  the 
wheel;  so  that,  when  laid  together,  the  shape  of  the  complete 
wheel  was  found.  The  blunt  ends  of  these  juxtaposed  wedges 
rested  upon  the  periphery  of  the  axle  box,  which  carried  a  flange, 


10 


SELF-PROPELLED    VEHICLES, 


or  vertical  disc,  forged  in  one  piece  with  it,  so  as  to  rest  on  the 
inside  face  of  the  wheel.  This  flange  was  pierced  at  intervals  to 
hold  bolts,  each  penetrating  one  of  the  spokes,  and  forming  the 
"hub"  with  a  plate  of  corresponding  diameter  nutted  upon  the 
outer  face  ofthewheel.  The  through  axle  shaft,  formed  in  one  piece 
and  rotatable,  carried  secured  to  its  extremities,  when  the  wheel 
was  set  in  place,  two  triangular  lugs,  oppositely  disposed  and 
formed  on  radii  from  the  nave.  The  outer  hub-plate  carried 


Fio.  9.— Church's  Three-wheel  Coach  (1833),  drawn  from  an  old  woodcut,  showing  for- 
ward spring  wheel  mounted  on  the  steering  pivot. 

similarly  shaped  and  disposed  lugs,  and  the  driving  was  effected 
by  the  former  pair,  turning  with  the  axle  spindle,  engaging  the 
latter  pair,  thus  combining  the  advantages  of  a  loose-turning 
wheel  and  a  rotating  axle.  Through  nearly  half  of  a  revolution  also 
the  wheel  was  free  to  act  as  a  pivot  in  turning  the  wagon,  thus 
obtaining  the  same  effect  as  with  Gurney's  arm  and  pin  drive 
wheels.  The  prime  advantage,  however,  was  that  the  torsional 
strain  was  evenly  distributed  through  the  entire  structure  by 
virtue  of  the  contact  of  the  spoke  extremities. 


MOTOR    VEHICLE  HISTORY. 


11 


Other  Notable  Coaches. — According  to  several  authorities, 
only  Gurney,  Hancock  and  J.  Scott  Russell  built  coaches  that 
saw  even  short  service  as  paying  passenger  conveyances — one  of 
the  latter's  coaches  was  operated  occasionally  until  about  1857. 
There  were,  however,  numerous  attempts  and  experimental  struc- 
tures, all  more  or  less  successful,  which  deserve  passing  mention 
as  embodying  some  one  or  another  feature  that  has  become  a 
permanence  in  motor  road  carriages  or  devices  suggestive  of  such 
features.  A  coach  built  by  a  man  named  James,  about  1829,  was 
the  first  on  record  to  embody  a  really  mechanical  device  for  al- 


Fio.  Id— James'  Coach  (1829),  the  "  first  really  practical  steam  carriage  built."    Drawn 

from  an  old  wood  cut. 

lowing  differential  action  of  the  rear,  or  driving,  wheels.  Instead 
of  driving  on  but  one  wheel,  as  did  Gurney,  or  using  clutches, 
like  some  others,  he  used  separate  axles  and  four  cylinders,  two 
for  each  wheel,  thus  permitting  them  to  be  driven  at  different 
speeds.  This  one  feature  entitles  his  coach  to  description  as  the 
"first  really  practical  steam  carriage  built."  Most  of  the  others, 
if  the  extant  details  are  at  all  correct,  must  have  been,  except  on 
straight  roads,  exceedingly  unsatisfactory  machines  at  best.  Ac- 
cording to  the  best  information  on  the  subject,  a  certain  Hills, 
of  Deptford,  was  the  first  to  design  and  use  on  a  carriage,  in  1843, 
the  compensating  balance  gear,  or  "jack  in  the  box,"  as  it  was 
then  called,  which  has  since  come  into  universal  use  on  motor 
vehicles  of  all  descriptions.  As  for  rubber  tires,  although  a 
certain  Thompson  is  credited  with  devising  some  sort  of  inflat- 
able device  of  this  description  about  1840-45,  there  seems  to  have 


12  SELF-PROPELLED   VEHICLES. 

been  little  done  in  the  way  of  providing  a  springy,  or  resilient, 
support  for  the  wheels.  We  have,  however,  some  suggestion  of 
an  attempt  at  spring  wheels  on  Church's  coach,  which  was  built 
in  1833.  According  to  an  article  in  the  Mechanics'  Magazine  for 
January,  1834,  which  gives  the  view  of  this  conveyance,  as  shown 
in  Fig.  9,  '  "The  spokes  of  the  wheels  are  so  constructed  as  to 
operate  like  springs  to  the  whole  machine — that  is,  to  give  and 
take  according  to  the  inequalities  of  the  road."  In  other  respects 
the  vehicle  seems  to  have  been  fully  up  to  the  times,  but,  judg- 
ing from  its  size  and  passenger  capacity,  as  shown  in  the  cut, 
it  is  reasonable  to  suppose  that  the  use  of  spring  wheels  was  no 
superfluous  ornamentation.  If  we  may  judge  further  from  the 
cut,  the  wheels  had  very  broad  tires,  thus  furnishing  another  ele- 
ment in  the  direction  of  easy  riding  on  rough  roads. 


CHAPTER  TWO. 

THE  MAKE-UP  OP  A  MOTOR  CARRIAGE. 

Modern  Motor  Vehicles. — Like  other  achievements  of  mod- 
ern science  and  industry,  motor  road  vehicles  represent  long  series 
of  brilliant  inventions  and  improvements  in  several  directions. 
As  now  constructed  they  are  of  three  varieties,  according  to  the 
motive  power  employed:  those  propelled  by  steam,  those  pro- 
pelled by  explosive  engines,  using  gasoline  or  some  other  spirit, 
those  propelled  by  electric  motors.  Considerable  has  been  done 
in  the  direction  of  producing  efficient  compressed  air  motors, 
which  have  been  applied  to  the  propulsion  of  heavy  trucks  and 
street  railway  cars,  but  for  ordinary  carriage  service  small  re- 
sults have  thus  far  been  attained.  Some  inventors  have  ex- 
pended their  energies  in  other  directions,  and  several  patents 
have  been  granted  in  the  United  States  for  coiled  spring  and 
clockwork  motors,  and  even  for  carriages  carrying  masts  and 
sails.  We  are  not  concerned,  however,  with  such  eccentric  de- 
vices, the  aim  of  this  book  being  merely  the  discussion  and  ex- 
planation of  successful,  practical  devices  actually  used  in  the 
construction  and  operation  of  motor  carriages. 

Conditions  of  Automobile  Construction. — In  one  way  the 

automobile  has  a  history  very  like  that  of  the  railway  carriage. 
At  first  both  were  devised  as  suitable  substitutes  for  the  horse- 
drawn  vehicle,  and,  as  a  consequence,  began  by  following  certain 
traditions  of  construction,  which  have  proved  very  like  hindrances 
to  progress.  The  first  railway  passenger  coaches  were  ordinary 
road  wagons,  several  of  which  were  coupled  together,  so  as  to 
be  drawn  along  a  grooved  tramway.  Later,  with  the  introduc- 
tion of  flanged  wheels  and  heavier  constructions,  several  carriage 
bodies  were  mounted  on  one  running  truck,  which  gave  the 
familiar  compartment  coaches  with  vis-a-vis  seats,  still  used  in 

is 


14  SELF-PROPELLED   VEHICLES. 

England  and  most  of  the  countries  of  Continental  Europe.  Only 
when  the  theory  of  railway  car  construction  departed  entirely 
from  the  models  and  traditions  of  road  wagons  in  the  adoption 
of  the  American  passenger  coach,  did  the  day  of  real  progress 
and  comfortable  travel  begin.  In  similar  fashion  many  of  the 
greatest  constructional  problems  of  automobiles  may  be  most 
readily  solved,  both  for  the  designer  and  the  operator,  in  recog- 
nizing the  fact  that  they  resemble  horse  carriages  in  no  other 
respect  than  that  both  have  similarly  appearing  bodies,  mounted 
on  four-wheel  frames,  and  run  on  ordinary  highways. 

Essential  Elements  of  an  Automobile. — While  in  this  age  of 
the  world  it  is  impossible  to  assert  that  any  device  is  perfected, 
or  that  any  has  reached  a  finality,  it  is  admissible  to  assume,  for 
practical  purposes,  that  recognized  standards  of  construction  are 
permanent.  Undoubtedly,  the  automobile  of  the  future  will  pos- 
sess many  features  now  unsuspected,  but  it  is  with  the  auto- 
mobile of  to-day  that  we  have  to  do.  We  will  take  up  the  essen- 
tial features  in  turn,  therefore,  describing  their  construction  and 
explaining  their  uses.  These  may  be  summed,  as  follows : 

1.  The  power  developed  by  a  motor  carried  on  the  running 
gear  is  applied  to  the  rear  wheels,  or  to  a  rotating  shaft  to  which 
they  are  secured. 

2.  The  two  driven  wheels  must  be  so  arranged  as  to  rotate 
separately,  or  at  different  speeds,  as  in  turning  corners.     For 
this  reason,  the  compensation  or  balance  gear  is  an   essential 
element. 

3.  The  two  forward  or  steering  wheels,  studded  to  pivots  at 
either  end  of  a  rigid  axle-tree,  must  be  arranged  to  assume  dif- 
ferent angles  in  the  act  of  turning,  in  order  that  the  steering  may 
be  positive  and  certain. 

4.  The  body  of  the  vehicle  must  be  set  relatively  low,  or  the 
wheel-base,  the  length  between  forward  and  rear  wheel-centres, 
must  be  relatively  long,  in  order  to  obtain  the  best  effects  in 
traction,  steering  and  safety. 


MAKE-UP  OF  A  MOTOR  CARRIAGE.  15 

5.  The  springs  must  be  of  such  strength  and  flexibility  as  to 
neutralize  vibration,  absorb  jars  and  compensate  any  unevenness 
in  the  roadway. 

6.  The  distance  between  the  motor  and  the  driven  wheels  must 
be  fixed  by  adjustable  radius  rods,  or  reaches,  in  order  that  the 
drive  may  not  be  interrupted  by  the  vibrations  of  travel. 

7.  The  wheels  must  be  shod  with  pneumatic,  or  other  forms 
of  tires,  of  sufficient  resiliency  to  protect  the  machinery,  running 
gear  and  passengers  from  the  jars,  otherwise  inevitable  at  high 
speeds  on  ordinary  highways. 

8.  Positive  and  powerful  brakes  must  be  provided,  in  order 
to  secure  effective  checking  of  motion,  whenever  required. 

9.  All  parts  must  move  with  as  little  friction  as  possible,  in 
order  to  save  power  for  traction.    For  this  reason,  ball  or  roller 
bearings  are  generally  used  on   all   rotating   shafts  of  motor 
carriages. 

10.  Convenient  and  efficient  means  for  ready  and  generous 
lubrication  of  moving  parts  is  a  constant  necessity. 

11.  Balance  of  parts  and  stable  constructions  are  required  to 
reduce  wear  and  friction. 

12.  Simplicity    of    structure,    ease    of    handling    and    repair. 
These  are  the  prime  requisites  of  the  best  automobile. 

13.  All  working  parts  must  be  of  sufficient  size,  weight  and 
strength  to  endure  the  jars  of  travel,  and  to  be  serviceable  under 
all  conditions.    There  may  be  some  advantages  in  the  light  con- 
structions,  formerly  supposed  to  be  essential,  but  present-day 
practice  recognizes  the  evident  fact  that  strength  and  durability 
are  the  more  important  considerations. 


CHAPTER  THREE. 

COMPENSATION  AND  COMPENSATING  DEVICES. 

Automobile  Driving  and  Compensation. — The  power  of  the 
motor  is  applied  either  to  the  centre-divided  rotating  rear  axle,  or 
to  a  rotating  jack-shaft  parallel  to  it,  thence  by  chain  and  sprocket 
to  the  two  wheels,  turning  loose  on  a  dead  rear  axle.  In  both 
cases  the  drive  is  through  a  device  known  as  the  differential  or 
compensating  gear.  Any  device  that  will  admit  of  a  steady  drive 
in  straight-ahead  running,  a  difference  of  speed  in  the  two  drive- 
wheels  in  turning  corners,  and  a  rapid  restoration  of  normal  con- 
ditions after  the  turn  is  completed,  is  usable  for  this  purpose. 
There  is,  however,  another  necessary  function,  which  may  not  be 
omitted, — the  differential  must  also  be  a  "balance  gear."  That 
is  to  say,  it  must  combine  with  the  function  of  compensation  an 
even  or  balanced  transmission  of  power  to  both  wheels.  Each 
wheel,  so  long  as  it  is  in  motion,  must  be  driven  with  the  same 
degree  of  power.  At  no  time,  even  on  short  turns  when  one 
wheel  is  stationary,  acting  as  a  pivot,  is  it  permissible  that,  say 
two-thirds  of  the  power,  be  sent  to  one  drive-gear,  and  one-third 
to  the  other.  The  power,  transmitted  from  the  centre  of  the  di- 
vided axle  or  jack-shaft,  must  always  be  the  same  in  both  direc- 
tions, even  though  one  wheel  be  stationary. 

Compensation  and  Balancing. — For  example,  the  device 
shown  in  Fig.  n  is  an  excellent  specimen  of  a  differential  or 
compensating  gear  that  is  not  also  a  balance  gear.  As  may  be 
seen,  it  consists  of  a  large  internal  gear  wheel,  C,  within  which 
and  rotating  about  the  same  axis  is  a  smaller  external  gear  or 
spur  wheel,  B, — the  two  engaging  the  spur  pinions,  A,  A,  as 
shown.  The  large  internal  gear  turns  on  the  axle  of  one  wheel, 
the  smaller  or  spur  wheel  on  the  opposite  one,  and  power  is 
applied  through  the  pinions  hung  on  radii  of  the  sprocket.  The 

16 


COMPENSATING    DEVICES.  17 

result  is  that  the  power-driven  pinions  transmit  more  power 
to  the  internal  gear,  because  of  its  greater  diameter,  than  to  the 
spur  gear,  thus  giving  one  wheel  a  tendency  to  revolve  more 
rapidly  than  the  other.  This  device  was  formerly  used  on  foot- 
propelled  tricycles,  and  is  perfectly  suitable  for  a  two-track  ma- 
chine of  this  description,  in  which  the  steering  wheel  is  set  di- 
rectly ahead  of  one  of  the  drivers,  so  as  to  progress  on  the  same 
track. 


Fie.  11.— A  form  of  Differential  Gear  formerly  used  on  Tricycles.  The  studs 
of  the  pinions,  AA,  are  set  in  spokes  of  the  sprocket,  turning  on  their 
own  axes  only  when  either  of  the  wheels  of  the  vehicle,  attached  re- 
spectively to  B  and  C,  cease  rotating,  as  in  the  act  of  turning. 

Automobile  Balance  Gears. — The  most  familiar  form  of  bal- 
ance gear  for  compensating  the  drive  wheels  of  motor  carriages 
is  the  bevel.  This  is  the  original  form  of  the  device,  and  was 
used  on  steam  road  wagons  as  early  as  1843.  As  shown  in  figs. 
12  and  13,  the  sprocket  or  drive  wheel  has  secured  to  its  inner 
rim  several  studs  carrying  oevel  pinions,  which,  in  turn,  engage  a 
bevel  gear  wheel  on  either  side  of  the  sprocket.  These  gear 
wheels,  last  mentioned,  are  rigidly  attached  on  either  side  to  the 
inner  ends  of  the  centre-divided  axle-bar,  one  serving  to  turn  the 
left  wheel,  the  other  the  right.  When  power  is  applied  to  the 
sprocket,  causing  the  vehicle  to  move  straight  forward,  it  may 
be  readily  understood  that  the  bevel  pinions,  secured  to  the 
sprocket,  instead  of  rotating,  which  would  mean  to  turn  the  drive 


18  SELF-PROPELLED  VEHICLES. 

wheels  in  opposite  directions,  remain  motionless,  acting  simply 
as  a  kind  of  lock  or  clutch  to  secure  uniform  and  continuous  rota- 
tion of  both  wheels.  So  soon  as  a  movement  to  turn  the  vehicle 
is  made,  at  which  time  the  wheels  tend  to  move  with  different 
speeds,  the  resistance  of  the  wheel  nearer  the  centre,  on  which 
the  turn  is  made,  tending  to  make  it  turn  more  slowly  than  the 
other,  as  anyone  may  readily  observe,  these  pinions  begin  ro- 
tating on  their  own  axes.  Thus,  while  allowing  the  pivot  wheel 


FIG.  12.  FIG.  13. 

FIGS.  12  and  13. — Bevel  Gear  Differentials.  The  sprocket  gear  carries  three 
bevel  pinions  set  on  studs  on  three  of  its  radii.  These  pinions  mesh 
with  bevel  wheels  on  either  side,  which  wheels  are  attached  at  the  two 
Inner  ends  of  the  divided  axle  shaft.  The  spur  drive  has  two  pinions 
rotating  on  radii,  and  shows  the  action  to  better  advantage. 

to  slow  up  or  remain  stationary,  as  conditions  may  require,  they 
continue  to  urge  forward  the  other  at  the  usual  speed.  The 
principle  involved  in  the  device  may  be  readily  expressed  under 
four  heads : 

1.  When  the  resistance  offered  by  the  two  drive  wheels  and 
attached  gear  is  the  same,  as  when  the  carriage  is  driven  forward, 
the  pinions  cannot  rotate. 

2.  When  the  resistance  is  greater  on  the  one  wheel  than  on  the 
other,  they  will   rotate  correspondingly,  although   still  moving 
forward  with  the  wheel  offering  the  lesser  resistance. 

3.  The  pinions  may  rotate  independently  on  one  gear  wheel, 
while  still  acting  as  a  clutch  on  the  other,  sufficient  in  power  to 
carry  it  forward. 


COMPENSATING  DEVICES. 


19 


4.  If  a  resistance  be  met  of  sufficient  power  to  stop  the  rotation 
of  both  wheels  and  their  axles,  the  condition  would  affect  the 
entire  mechanism,  and'  the  pinions  would  still  remain  stationary 
on  their  own  axes,  just  as  when  in  the  act  of  transmitting  an  equal 
movement  to  both  wheels. 

For  light  carriage  work  the  sprocket  or  spur  drive  generally 
carries  two  pinions,  as  shown  in  the  figure,  but  in  larger  vehicles 
the  number  is  increased  to  three,  four,  or  six,  and  the  size,  pitch 


Fie.  14.— The  Riker  Hub  Enclosed  Differential.  A  Is  the  rotating  sleeve 
carrying  the  drive  spur.  It  is  bolted  to  the  yoke  carrier,  B,  and  the 
flange  piece,  K,  as  shown.  C  and  C  are  the  studs  of  the  bevel  pinions 
attached  to  the  yoke  carrier,  B.  F  is  the  bevel  gear  wheel  keyed  to  the 
rotating  through  axle  shaft,  G,  whose  opposite  end  is  rigidly  attached 
to  the  other  hub.  The  bevel  gear,  E,  is  keyed  to  the  in-flanged  portion 
of  the  hub.  D,  turning  on  the  reduced  portion,  H,  of  the  rotating  axle 
shaft. 

and  number  of  the  teeth  are  varied,  according  to  requirements. 
Of  course,  it  is  essential  that  the  equalizing  gears  be  properly 
chosen  for  the  work  they  are  to  perform,  in  the  matter  of  the 
number  of  the  pinions  and  of  their  teeth,  as  well  as  of  the  metal 
used,  on  account  of  the  great  strain  brought  to  bear  on  them. 
With  even  the  best  made  bevel-gears  there  is  a  danger  of  end 
thrust  and  a  tendency  to  crowd  the  pinions  against  the  collars, 
with  consequently  excessive  wear  on  both.  The  result  is  a  loose- 
ness that  demands  constant  adjustment. 

Spur  Compensating  Gears. — In  order  to  avoid  the  difficulties 
encountered  with  bevel  gears,  spur-gears  were  invented,  and  are 


|0  SELF-PROPELLED  VEHICLES. 

now  increasing  in  popularity.  In  this  variety  the  theory  of  com- 
pensation is  the  same  as  with  bevel  gearing;  a  divided  axle  or 
jack  shaft  whose  two  inner  ends  carry  gear  wheels  cut  to  mesh 
with  pinions  attached  to  the  sprocket  pulley.  These  pinions  are, 
however,  set  in  geared  pairs,  with  their  axes  at  right  angles  to 
the  radius  of  the  sprocket,  which  is  to  say  parallel  to  its  axis.  As 
will  be  seen  in  the  accompanying  illustrations,  the  pinions  of  each 


PIG.  16. — One  form  of  Spur  Differential  or  Balance  Gear.  The  two  inner 
ends  of  the  divided  axle  shaft  carry  spur  wheels,  which  mesh  each  with 
one  of  every  pair  of  the  three  pairs  of  spur  pinions  shown.  As  these 
pinions  mesh  together  both  rotate  on  their  axes  as  soon  as  turning  of 
the  wagon  begins. 

pair  are  set  alternately  on  the  one  side  or  the  other  of  the  sprocket, 
meshing  with  one  another  in  about  half  of  their  length,  the  re- 
mainder of  each  being  left  free  to  mesh  with  the  axle  spurs  on 
the  one  or  other  side.  The  model  here  has  three  pairs  of  pinions, 
one  of  each  meshing  with  either  of  the  axle  gears.  With  some 
differentials  the  divided  axle  carries  internal  gears,  with  others 
true  spur-wheels.  The  operation  is  obvious.  When  the  vehicle 
is  turning,  one  rear  wheel  moves  less  rapidly,  causing  the  pinion 
with  which  it  is  geared  to  revolve  on  its  mate,  which,  in  turn, 
revolves  on  its  own  axis,  although  still  engaging  the  gear  of  the 
opposite  and  moving  wheel  of  the  vehicle.  The  motion  is  thus 
perfectly  compensated,  without  the  wear  and  thrust  inevitable 
with  bevels. 

Disadvantages  of  a  Divided  Axle  Shaft. — The  practice  of  di- 
viding the  axle  or  jack  shaft  at  the  centre  is  a  source  of  weakness 


COMPENSATING  DEVICES. 


which  was  recognized  and  provided  against  long  since.  Although, 
theoretically,  the  shaft  is  divided  at  the  centre,  the  construction 
now  usually  adopted  is  to  mount  one  wheel  on  the  axle  and  the 
other  on  a  hollow  shaft  or  sleeve  which  works  over  it.  The  solid 
shaft  can  then  be  made  as  long  as  the  width  of  the  vehicle,  the 
differential  gear  wheel  belonging  to  it  being  secured  about  mid- 
way in  its  length.  This  hollow  shaft  or  sleeve  is  about  half  as 
long,  so  that  its  gear  is  attached  at  its  inner  end  and  is  immedi- 


Fio.  16.— Section  through  the  axis  of  a  bevel  gear  differential  train,  show 
ing  two  bevel  pinions  attached  at  top  and  bottom  of  the  sprocket  drum, 
and  two  bevel  gear  wheels  one  on  the  through  axle  shaft,  the  other 
on  a  rotating  sleeve  and  through  the  axis  of  a  bevel  gear  differential,  showing 
two  bevel  gears  keyed  to  rotating  sleeves  over  an  internal  through  axle 
or  liner  tube. 

ately  opposite  the  other,  both  meshing  with  the  pinions  attached 
to  the  sprocket.  Such  a  construction  involves  no  other  variation 
from  the  method  of  attaching  the  differential  gear-train  to  the 
ends  of  the  divided  axle  than  making  the  eyes  of  the  two  gear 
wheels  of  different  diameters,  so  as  to  fit  the  axle  shaft,  on  the 
one  side,  and  the  hollow  axle,  or  sleeve,  on  the  other.  The 
sprocket  is  then  inserted  between  them,  being  held  in  position  by 
the  meshing  of  the  axle  gears  with  the  pinions,  itself  turning 
loose  on  the  solid  through  shaft.  The  inner  solid  axle  shaft  is 
secured  in  position  by  suitable  collars. 


22  SELF-PROPELLED   VEHICLES. 

Through  Axle  Shaft  and  Liner  Tube. — Another  typical 
method  for  securing  the  strength  and  solidity  of  a  through  axle 
shaft  is  to  attach  both  wheels  to  hollow  axles  of  the  same  di- 
ameter, each  of  which  carries  on  its  opposite  or  inner  end  the 
gear  wheel  of  the  differential  train.  Another  tube,  called  the 
"liner  tube,"  of  the  same  length  as  the  width  of  the  vehicle,  is 
then  inserted  in  the  hollow  axles,  and  the  two  are  brought  to- 
gether so  as  to  bear  upon  a  collar  secured  to  the  .centre  of  the  liner 
tube.  The  sprocket  and  differential  pinion  train  are  inserted  and 
held  in  place  in  a  fashion  similar  to  that  used  in  the  previous  de- 
vice, the  inter-meshing  of  the  bevels  serving  to  support  it. 

With  either  of  these  arrangements  it  is  customary  to  place  the 
differential  nearer  one  wheel. 


Pic.  17.— A  Universal  Joint  Differential.  The  sprocket  or  spur  drive  turns 
the  sleeve  which  holds  the  gear  case  here  shown  in  section.  So  long  as 
travel  is  straight  ahead  neither  pinion  rotates  on  Its  axis,  but  as  soon 
as  a  turn  Is  made  rotation  begins,  thus  allowing  compensation  of  the 
motion  of  the  two  wheels  of  the  wagon. 


CHAPTER  FOUR. 

THE  DRIVING  GEAR. 

Types  of  Gear  Connection. — In  the  transmission  of 
power  to  the  driven  wheels  several  methods  are  followed  in  prac- 
tice. These  vary  according  to  the  size  and  weight  of  the  vehicle 
and  the  character  of  the  motor,  also  according  to  the  individual 
preference  of  the  designer.  One  system  is  to  be  preferred  to 
another  on  account  of  real  or  supposed  strength  and  reliability, 
or  of  its  efficiency  in  economizing  power.  Thus  it  is  that  a  certain 
system  of  transmission,  declared  by  one  builder  fit  only  for  light 
cars,  is  used  by  another  on  heavy  ones,  and  the  opposite  is  also 
the  case. 

At  the  present  time,  we  may  distinguish  seven  varieties  of 
drives : 

1.  By  chain  and  sprocket  connection  from  the  main  shaft — in 
gasoline  carriages,  from  the  second  shaft — direct  to  the  differen- 
tial on  the  rear  axle. 

2.  By  chain  and  sprocket  to  each  rear  wheel  separately,  from 
a  transverse  jack  shaft,  driven  direct  from  the  motor  and  carry- 
ing the  differential  drum. 

3.  By  longitudinal  propeller  shaft  from  the  motor  to  the  rear 
axle,  power  being  transmitted  by  bevel  gears  to  the  differential 
drum.    This  method  of  driving  is  usually  followed  between  the 
motor  shaft  and  the  jack  shaft  in  the  type  of  transmission  just 
described. 

4.  By  spur  gear  connections  from  the  motor  shaft  to  the  dif- 
ferential drum  on  the  rear  axle,  as  on  a  few  gasoline  carriages, 
some  cycles  and  on  nearly  all  electric  vehicles. 

5.  By  spur  connection  to  an  external  or  internal  gear  on  each 
of  the  rear  wheels  from  a  transverse  differential  shaft,  as  in 
some  electric  vehicles. 

23 


24  SELF-PROPELLED   VEHICLES. 

6.  By  spur  connection  to  an  external  or  internal  gear  on  each 
of  the  drive  wheels,  between  each  wheel  and  a  separate  motor, 
without  using  a  differential  device  of  any  kind,  used  only  on 
electric  vehicles. 

7.  By  using  the  hub  of  each  wheel  as  one  element  of  the 
motor;  as  in  the  so-called  electric  "hub  motors,"  or  in  cycles 
where  the  motor  is  enclosed  within  the  body  of  a  suspended  wire 


FIG.  18.— Single  wheel  of  a  type  of  car  having  double-chain  drive  from  \ 
jack-shaft  parallel  to  the  dead  rear  axle 

wheel,  as  in  a  cage.     A  similar  device  has  been  tried  for  steam 
carriages,  but  without  conspicuous  success. 

Direct  drive  by  a  crank  on  the  drive  wheel,  axle  or  jack  shaft, 
has  been  tried  in  recent  times  only  on  one  or  two  bicycles,  among 
them  the  Holden.  The  so-called  "direct  drive"  claimed  for  some 
modern  steam  carriages,  is  really  a  spur  drive;  one  spur  carry- 
ing the  crank  pins  of  the  engine,  the  other  being  hung  on  the 
differential  axis. 


THE  DRIVING  GEAR.  25 

Chain  and  Sprocket  Drive. — A  type  having1  a  chain  and 
sprocket  to  drive  each  rear  wheel  separately  is  shown  in  figs. 
19,  20.  On  some  large  vehicles  of  early  design  a  single 
chain  connection  between  the  motor  main  shaft,  or  the 
transmission  gear,  and  the  differential  sprocket  on  the  rear  axle, 
was  frequently  employed.  However,  it  was  early  found  entirely 


FIGS.  19,  20.— Part  Sectional  Elevation  and  Plan  of  the  Riker  Locomobile 
Chassis,  showing  arrangement  of  jack  shaft,  or  countershaft,  and  double 
chain  drive. 


unsuitable  for  any  except  the  lighter  types  of  vehicle.  With 
heavy  cars  of  long  wheel  base,  as  at  present  constructed,  it  would 
be  absurd. 


26  SELF-PROPELLED  VEHICLES. 

Jack=Shaft  and  Separate  Wheel  Drive. — This  construction 
is  found  on  practically  all  heavy  cars  using  chain  drive.  Briefly 
described,  the  system  includes : 

I.  A  transverse  centre-divided  jack-shaft  driven  direct  from 
the  motor,  or  through  the  transmission  gear,  by  bevels  to  the 
differential  drum. 

2,.  A  sprocket  at  each  end  of  the  jack-shaft  for  providing  chain 
connection  to  the  hub  of  each  rear  wheel. 

3.  Driven  wheels  turning  loose  at  the  ends  of  a  dead  axle-tree, 
as  in  a  horse  carriage,  each  being  driven  by  a  separate  chain  on  a 
sprocket  secured  to  its  hub. 

The  advantages  that  may  be  found  in  this  arrangement  are : 
I.  The  superior  strength  and  rigidity  of  construction  to  be 
found  in  an  undivided  rigid  rear  axle. 


FIG.  21.— Section  of  a  driving  chain,  showing  arrangement  of  the  rollers  and 
side  links. 

2.  The  use  of  shorter  chains,  involving  a  greater  immunity 
from  ordinary  chain  troubles,  and  greater  ease  of  adjustment 

3.  Greater  ease  in  removing  and  repairing  the  driven  wheels. 

4.  Steadier  and  better-balanced  driving,  with  a  corresponding 
economy  of  power. 

Troubles  with  Two=Chain  Drive. — Formerly,  the  use  of  two 

chains  was  found  to  involve  more  noise  and  clatter  than  is  found 
with  one.  However,  with  roller  chains,  now  in  nearly  universal 
use  on  motor  vehicles,  this  annoyance  is  greatly  reduced.  Much 
noise  is  caused  with  a  loose  chain  by  the  jumping  of  links 


THE  DRIVING  CHAR.  27 

Driving  Chains  and  Their  Use. — Two  varieties  of  sprocket 
driving  chain  are  used  on  motor  vehicles : 

1.  Roller  chains. 

2.  Block  chains. 

Both  have  their  advocates,  who  argue  variously  the  advan- 
tages of  superior  strength  or  superior  driving  qualities  and 
noiselessness. 

The  block  chain  is  made  of  a  series  of  blocks,  properly  shaped 
to  fit  the  periphery  of  the  sprocket,  each  joined  to  similar  blocks 
before  and  after  by  side  links  bolted  through  the  body  of  the 
block. 

The  roller  chain  is  made  of  a  series  of  pairs  of  rollers,  known 
as  centre  blocks,  similarly  joined  by  side  links.  Each  roller  ro- 
tates loose  on  a  hollow  core,  which  is  turned  to  smaller  diameter 
at  either  end,  to  fit  a  perforated  side  piece  joining  the  rollers  into 
pairs.  The  side-links  are  set  over  these  side  pieces  and  bolted  in 
place  through  the  cores. 

In  operation,  a  block  chain  with  generous  slack  is  liable  to 
meet  the  sprocket  with  a  continual  clapping  that  at  high  speed 
becomes  a  continuous  rattle.  The  roller  chain  is  largely  immune 
from  this  trouble.  Furthermore,  being  obviously  easier  in  oper- 
ation, it  economizes  power.  Some  authorities  estimate  its  effi- 
ciency in  driving  as  high  as  98  per  cent,  under  favorable  con- 
ditions. 

Strength  of  Driving  Chains. — In  point  of  strength  a  compari- 
son between  block  and  roller  chains  of  the  same  sizes  is  inter- 
esting, as  showing  the  insuperable  superiority  of  the  latter  va- 
riety. The  following  tables  are  supplied  by  a  prominent  chain 
and  gear  manufacturer.  For  Diamond  non-detachable  B-block 
chains : 


PITCH 

WIDTH 

BREAKING  LOAD 

i" 
i" 

iX" 

%«,  y*  or  # 
%6,  ft  or  % 

y* 

1,600  Ibs. 
2,500     " 
5,000    " 

28 


SELF-PROPELLED  VEHICLES 


For   three    different   makes   of   roller  chains,   the   following 
figures  are  given: 


PITCH 

WIDTH 

DIAMETER 
OF  ROLLER 

BREAKING  LOAD 

X" 

#,  %e,  or  X 

1,200         Ibs. 

X" 

#,  %6,  or  X 

1,400 

Jr 

5Aa  or  ^ 

15/33 

4,000 

fi  or  |4 

9it 

4,500 

i" 

f6  or  ^ 

%«  or  # 

5,000  or  5,500 

*  V 

j£  or  ^ 

f^  or  %" 

5,500  to  7,500 

i>£" 

?i  or  M 

K'  to  ft 

12,000 

13^"' 

I 

I 

19,000 

2' 

»x 

i>i 

25,000 

For  the  sizes  of  chain  here  specified,  the  breaking  strength  of 
the  roller  chain,  or  the  average  limit  of  its  pulling  power,  is  shown 
to  be  between  -J  and  §  greater  than  that  of  the  block  chain. 

Under  ordinary  conditions  of  use,  the  safe  working  load  of 
a  chain  varies  between  i-io  and  1-40  the  tensile  strength.  This 
latter  is  generally  very  high.  According  to  the  statements  of  a 
prominent  chain  manufacturer : 

"A  24  inch  pitch  roller  chain  has  sufficient  strength  to  drive  a  six-ton 
truck  a  number  of  hours.  The  breaking  of  this  chain  will  not  occur  until 
the  pitch  of  chain  and  sprocket  has  elongated,  or  they  become  unlike;  then 
the  chain  climbs  the  teeth,  which  act  as  wedges,  exerting  enormous  strain, 
quickly  wrecking  the  chain." 


Operation  of  a  Driving  Chain. — The  same  authority  explains 
that: 

"The  rivets  of  a  chain  act  as  a  number  of  auxiliary  shafts,  and  operate 
under  friction  in  the  same  manner,  but  with  less  favorable  conditions  than 
the  shaft  that  drives  them.  In  order  to  adapt  the  chain  to  the  load  it 
must  carry,  he  recommends  larger  sizes  than  are  at  present  generally  used, 
explaining  that  the  limit  of  fatigue  should  approach  closely  the  ultimate 
strength,  and,  with  these  factors  attained,  the  size  of  chain  should  be 
selected  which  permits  sufficient  rivet  wearing  surface.  This  additional 
size  and  weight  is  objected  to  by  automobile  builders,  on  account  of  what 
they  term  'clumsiness,  weight  and  expense.' " 


THE,  DRIVING  GEAR. 


POSITION 

TOOTH    "A"    IN 
ACTION 


Z"   POSITION 
LINK  HAS  SLIPPED  UP 
'ON  TOOTH  "A"  CHAIN 
ABOUT  TO  SLIP 
OFF  THE  TOOTH 


3*  POSITION  CHUN  HAS  SLIPPED  orr  TOOTH  -A" AND  TPANSFEBBEO  LOAD  TO  TOOTH  "a: 

IPS  BACK  UNTIL 
rCS  IN  CONTACT 

CHAIN  OPtVLS  x<^  ^fff^  — ~ ~-*~"~<':*:-'4.     (          ><  WITH  LINK  WITH  CON- 

SEQUENT JAR 
AND  NOiaL. 


Fics.  22,  23,  24. -Diagrams  Illustrating  th*  operation  of  driving  with  a  roller 
chain  and  sprocket. 


30  SELF-PROPELLED  VEHICLES. 

Double  Chain  and  Bevel  Drives. — For  commercial  and  high 
powered  vehicles,  there  is  much  in  favor  of  the  chain  drive,  but 
for  machines  of  light  and  medium  power  the  propeller  shaft  and 
bevel  gear  is  the  more  desirable. 

The  chief  advantage  of  the  chain  drive  is  great  strength  with  light 
weight.  The  rear  axle  being  of  the  dead  type  is  of  simpler  construction 
than  the  divided  axle  required  for  the  bevel  drive  and  it  is  perfectly 
adapted  to  support  the  car.  Against  this  is  the  objectionable  noise  made 
by  the  chain,  the  difficulty  of  keeping  it  clean  and  lubricated,  also  the  wear 
and  stretching.  The  bevel  drive  being  enclosed  in  a  tight  casing  has  the 
advantage  of  perfect  lubrication,  with  all  parts  running  in  oil  and  freedom 
from  dust.  The  quiet  running  of  the  bevel  drive,  more  than  offsets  its 
disadvantages  such  as  the  necessary  divided  live  axle  with  the  heavy 
bracing  required  so  that  the  imposed  weight  may  not  bend  or  spring  it  out 
of  line.  The  popularity  of  the  bevel  drive  is  attested  by  its  general 
adoption  on  all  types  of  automobiles  except  the  high  powered  racing  pars 
and  commercial  trucks. 

Proportions  of  the  Sprocket. — In  the  design  of  a  chain- 
transmission  system,  the  proportions  of  the  sprocket  are  im- 
portant. According  to  reliable  data : 

"The  thickness  of  the  sprocket  at  pitch  line  should  be  from  1/32  to  1/16 
inch  less  than  the  length  of  the  roller,  according  to  pitch  of  chain.  Thick- 
ness of  tooth  on  outside  diameter  should  be  V-z  the  length  of  roller." 

The  number  of  teeth  is  as  important  a  consideration  on  a 
sprocket  as  on  a  gear  wheel.  In  both  cases  twelve  teeth  form 
the  average  of  good  efficiency.  This  is  explained  in  the  following 
quotation : 

"The  most  satisfactory  results  are  obtained  by  the  use  of  sprockets  having 
twelve  teeth  or  over.  A  smaller  number  may  be  used,  but  at  a  sacrifice  of 
efficiency  by  elongation  from  wear  of  chain,  wear  of  sprockets,  and  loss 
of  power,  experience  demonstrates  that  eight-tooth  sprockets  are  chain- 
wreckers  and  power-consumers.  Nine  teeth  will  give  only  fair  results, 
and  ten  and  eleven  teeth  can  only  be  termed  satisfactory  when  the  speed 
is  not  high  and  the  conditions  of  operation  are  unusually  favorable." 

Pitches  of  Chain  and  Sprocket. — It  is  impracticable  to  so 
design  a  driving  sprocket  that  the  chain  rollers  shall  fit  snugly 


THE  DRIVING  GEAR.  31 

between  the  teeth.     The  following  quotation  from  an  English  au- 
thority explains  the  situation : 

"A  chain  can  never  be  in  true  pitch  with  its  sprocket.  A  pair  of  spur 
gears  tend — to  a  certain  extent — to  wear  into  a  good  running  fit  with  each 
other,  but  a  chain,  if  made  to  fit  its  sprocket  when  new,  does  not  continue 
to  do  so  a  moment  after  being  made,  as  wear  at  once  throws  it  out.  This 
being  so,  it  must  be  put  up  with,  and  involves  the  consequence  that  a  chain 
can  only  drive  with  one  tooth  at  a  time,  supplemented  by  any  frictional 
"bite"  the  other  links  may  have  on  the  base  of  the  tooth  interspaces.  If 
the  chain  be  made  to  fit  these  accurately,  as  in  Fig.  25  (taking  a  roller  chain 
in  illustration),  it  is  obvious  that  the  least  stretch  will  cause  the  rollers 
AA  to  begin  to  ride  on  the  teeth  as  at  BB.  If,  however,  the  teeth  be  made 
narrow  compared  with  the  spaces  between  the  rollers,  a  considerable 
stretch  may  occur  without  this  taking  place.  The  roller  interspaces,  then, 
should  be  long,  to  permit  the  teeth  to  have  some  play  in  them,  while  re- 
taining sufficient  strength,  as  shown  in  Fig.  25  at  B. 


FIG.  25.— Diagrams  showing  the  behavior  of  a  chain  on  a  sprocket  of  equal 
pitch,  and  on  one  of  properly  unequal  pitch. 

"In  order  that  the  driving  sprocket  may  receive  each  incoming  link  of 
the  chain  without  its  having  to  slide  up  the  tooth-face,  it  should  be  of  a 
somewhat  longer  pitch  than  its  chain,  the  result  being  that  the  bottom  tooth 
takes  the  drive,  this  being  permitted  by  the  tooth-play  shown  in  Fig.  B. 
This  difference,  of  course,  gradually  disappears  as  the  chain  stretches.  The 
back  wheel  sprocket,  on  the  other  hand,  should  take  the  drive  with  its  top- 
most tooth,  and  hence  should  be  of  slightly  less  pitch  than  the  chain,  but 
as  the  pitch  of  the  latter  constantly  increases,  it  may  be  originally  of  the 
same  pitch.  The  only  remaining  point  with  regard  to  design,  and  one 
which  the  owner  of  a  car  may  easily  ensure,  is  that  the  number  of  teeth  in 
the  sprockets  should  be  prime  to  that  of  the  links  in  the  chain. 

Even  with  the  best  designed  sprocket,  as  each  tooth  in  turn 
passes  out  of  engagement  with  the  chain,  the  next  roller  must  be 
drawn  forward  through  an  appreciable  distance  before  engaging  a 


32  SELF-PROPELLED   VEHICLES. 

tooth.  This  causes  the  snap  and  rattle,  always  noticeable  in  chain- 
driven  vehicles,  and  is  an  important  factor  in  waste  of  driving 
power.  To  remedy  such  defects  some  have  suggested  >  the  use 
of  the  self-adjusting  silent  gear  chain,  so  successfully  used  in 
other  branches  of  mechanical  science.  The  difficulty  here,  how- 
ever, is  that  such  chains  must  be  drawn  tighter  than  those  gener- 
ally used  on  sprockets,  and,  unless  thoroughly  encased,  are  liable 
on  an  automobile  to  gather  dust  and  grit,  which  greatly  reduce 
their  durability. 

Care  of  Chains. — The  principal  points  to  be  observed  in  the 
use  and  care  of  sprocket  driving  chains  are : 

I.  To  maintain  the  proper  tension  in  order  to  avoid  whipping — 
which  is  liable  to  result  in  snapping  of  the  chain,  particularly  a 
long  one — and,  at  best,  involves  a  loss  of  driving  efficiency.  The 
chain  should  not  be  drawn  tight,  lest  a  similar  disaster  result. 
Some  slack  must  always  be  allowed. 

•2.  The  two  sprockets  should  always  be  kept  in  perfect  align- 
ment. In  the  case  of  double-chain  drive  from  a  counter-shaft 
parallel  to  the  rear  axle,  care  should  be  exercised  to  maintain  the 
parallelism,  even  preferring  a  somewhat  loose  chain  to  a  tight  one 
that  strains  the  counter-shaft. 

3.  If  a  link  shows  signs  of  elongation  it  should  be  replaced 
by  a  new  one  at  once. 

4.  Whenever  the  chain  is  removed  for  cleaning  or  other  pur- 
pose, it  should  be  carefully  replaced,  so  as  to  run  in  the  same  di- 
rection, as  formerly,  and  with  the  same  side  up.    Never  turn  the 
chain  around  or  reverse  its  direction  between  the  sprockets. 

5.  A  new  chain  should  not  be  put  upon  a  much-worn  sprocket, 

6.  A  conspicuous  difficulty  involved  in  the  use  of  driving  chains 
is  the  liability  to   clog   and   grind    with    sand,    dust   and    other 
abradents.     A  chain  should  be  occasionally  cleaned,  therefore, 
and,  what  is  more  important,  should  be  carefully  rubbed  with 
graphite  preparation,  which  is  the  best  lubricant  for  the  purpose, 


THE  DRIVING  GEAR.  33 

and  fills  the  chinks  otherwise  open  to  receive  dirt.    Furthermore, 
it  prevents  dust  from  adhering  to  the  surface  of  the  chain. 

7.  After  steady  use  for  a  more  or  less  extended  period,  the 
chain  should  be  removed  and  thoroughly  cleaned.  The  most 
approved  method  is  as  follows: 

Cleaning  the  Drive  Chain. — After  removing  the  chain,  cleanse 
first  in  boiling  water,  then  in  gasoline,  in  order  to  remove  all 
grease  and  dirt  whatever.  Any  break  or  defect  may  now  be 
plainly  discovered,  and  should  be  remedied  by  inserting  new 
links  for  those  disabled.  The  common  practice  is  then  to  boil 
the  chain  for  about  half  an  hour  in  mutton  tallow,  which  is 
thereby  permitted  to  penetrate  all  chinks  between  rolling  sur- 
faces, forming  an  excellent  inside  lubricant.  After  boiling,  the 
chain  is  hung  up  until  thoroughly  cool,  at  which  time  the  tallow 
is  hardened.  It  may  then  be  wiped  off  clean  and  treated  with  a 
preparation  of  graphite,  or  a  graphite-alcohol  solution  on  its 
inner  surface. 

Some  authorities  recommend  that  the  chain,  after  it  is  cleaned, 
should  be  soaked,  first,  in  melted  paraffin  for  an  hour  at  least, 
and  then  in  a  mixture  of  melted  mutton  tallow  and  graphite. 
After  each  soaking,  it  is  dried  and  wiped  clean. 

With  either  process,  a  daily  application  of  graphite  chain 
preparation  is  most  desirable. 

Looseness  of  Chains. — On  the  point  of  chain  adjustment,  the 
authority  quoted  above  writes  as  follows : 

"Shedding  of  chains  is  generally  brought  about  either  by  excessive  loose- 
ness or  want  of  alignment  between  the  sprockets  and  back  chain  wheels ; 
a  sufficient  transverse  rounding  of  the  tips  of  the  teeth  is  advisable  to 
diminish  the  chance  of  it.  A  shrowding  or  flange  on  each  side  of  the  teeth 
for  the  side  plates  of  the  chain  to  bear  on  is  certainly  desirable,  as  dimin- 
ishing the  wear  on  the  rollers  and  giving  a  certain  increase  of  frictional 
drive ;  but  it  is  not  always  provided.  It  may  be  here  noted,  as  a  reply  to 
a  question  occasionally  asked  by  untechnical  drivers,  that  where  there  is  a 
differential  on  the  countershaft  an  inequality  in  the  tightness  of  the  chains 
does  not  prevent  each  of  them  taking  its  share  of  the  driving;  and  it  is 
more  important  that  the  parallelism  of  the  countershaft  and  back  axles 
shall  be  maintained  than  that  the  chains  should  be  kept  equally  tight  at  the 
sacrifice  of  this." 


34 


SELF-PROPEL  LLD   VEHICLES. 


Propeller-Shaft  Transmission. — Transmission  of  power  by 
propeller  shaft,  through  bevel  gears,  to  the  rear  axle,  has  been 
adopted  by  a  number  of  designers,  and  seems  to  be  gaining  favor. 
It  would  seem  to  be  the  logical  outcome  of  the  jack-shaft  and 
double  chain  system  already  noticed,  since  the  bevel  drive  is 


FIGS.  26,  27.— Part  Sectional  Elevation  and  Plan  of  the  Decauville  Car, 
showing  general  arrangement  of  a.  propeller  shaft  drive  through  bevel 
gears  to  the  rear  axle. 

direct  to  the  rear  axle,  instead  of  to  the  transverse  jack-shaft. 
There  are  several  problems  and  difficulties  involved,  however, 
that  do  not  appear  in  other  types  of  transmission. 

i.  There  is  naturally  greater  opportunity  for  end-thrusts  on 
the  rear  axle  than  on  a  jack-shaft,  with  a  commensurate  wear  on 
the  parts  and  danger  of  breakage. 


THE  DRIVING  GEAR. 


35 


2.  Although  a  universally  jointed  shaft  connects  the  motor 
and  the  driving  bevel,  the  maintaining  of  perfect  steadiness  is 
difficult  and  various  lateral  stresses,  notably  the  tendency  of  the 
pinion  to  climb  upward  or  downward  over  the  teeth  of  the  gear, 
according  as  the  motion  is  straight  ahead  or  reversed. 

As  a  consequence  of  these  conditions,  ball  bearings  are  pro- 
vided to  take  the  thrust  of  the  large  bevel  gear  on  the  axle-shaft. 


FIG.  28.— Sectional  diagram  of  the  bevel-drive  of  the  Pierce  Car,  showing 
arrangement  of  the  propeller  shaft  and  location  of  the  thrust  bearings. 

FIG.  29. — Bevel  Driving  Apparatus  of  the  Peerless  Car,  A  and  B,  sleeve  and 
case  for  axles  and  gears;  D,  the  driven  gear;  E,  driving  pinion;  G,  ball 
bearings  on  B;  H,  H,  universal  couplings  on  the  differential;  K,  K,  K, 
adjustments;  L,  yoke  for  flexible  driving  shaft. 


A  slip-joint,  in  addition  to  the  universal  coupling  on  the  propeller- 
shaft,  compensates  for  the  varying  distance  between  the  speed 
gear  and  the  axle,  under  the  rise  and  fall  of  the  springs.  In  the 
Packard,  and  one  or  two  other  cars,  approximate  steadiness  of  the 
driving  pinion  is  attained  by  placing  the  speed  gear  directly  in 
front  of  the  rear  axle. 


36 


SELF-PROPELLED   VEHICLES. 


The  Haynes  Propeller  Drive. — The  Haynes  carriage  em- 
bodies an  interesting  variation  on  the  common  types  of  bevel 
drive,  having  as  the  driven  gear  a  kind  of  dished  crown  gear  or 
sprocket,  with  teeth  around  the  inturned  edge,  and,  as  the  driv- 
ing pinion  a  roller  gear,  in  which  a  number  of  rollers,  inclined 
inward  from  the  periphery,  serve  instead  of  teeth.  The  rotary 
tendency  of  the  differential  case,  under  stress  of  the  driving 
pinion,  is  avoided  by  the  use  of  a  vertical  stay-bar  projecting 
through  a  square  yoke  in  a  cross  bar  above  the  spring,  which 
serves  to  direct  the  stress  upward,  thus  removing  all  strain  from 


FIG.  30.— The    Haynes-Propeller-Shaft    Drive,    which    marks    a    decided    Im- 
provement on  common  types  of  bevel  drive. 

the  axle  casing.  Instead  of  the  usual  slip-joint,  consisting  of  a 
sliding  square-section  shaft,  a  "four-pronged  joint"  is  used.  In 
this  arrangement  a  flanged  hub  is  keyed  to  the  driving  shaft,  and 
carries  four  steel  pins,  which  project  forward,  entering  four 
holes  in  the  body  of  the  universal  joint.  Thus  the  torque  exerts 
no  torsional  stress  other  than  a  shearing  force  upon  the  pins, 
which  has  been  proved  of  no  serious  importance.  The  advan- 
tages claimed  for  this  device  are: 

i.  Superior  strength,  as  found  in  the  comparison  between  the 
long,  narrow  teeth  of  a  bevel  gear  and  the  short,  thick  teeth  of 
the  Haynes  sprocket. 


THE  DRIVING   GEAR. 


37 


2.  Elimination  of  thrust,  in  the  fact  that  two  rollers  are  always 
in   full  engagement  with  the  sprocket,  one  always  entering  a 
hollow  as  another  passes  out  of  engagement. 

3.  Silent  operation,  by  combining  the  advantages  of  bevel  and 
roller  chain  drive,  while  avoiding  their  inherent  difficulties. 


FIG.  31. — Diagrams  to  Illustrate  different  constructions  of  shaft  drive. 
The  upper  figure  shows  the  ordinary  construction  in  which  the  rear 
shaft  length  is  at  an  angle  with  the  engine  shaft.  The  lower  figure 
illustrates  the  "straight  line  drive"  in  which  the  several  shaft 
lengths  are  placed  in  a  straight  line,  thus  eliminating  friction  and 
wear  due  to  angularity  at  the  universal  joint. 


The  Straight  Line  Drive. — Several  manufacturers  of  automo- 
biles, of  the  shaft  driven  type,  have  incorporated  in  their  designs 
what  is  known  as  the  straight  line  drive.  In  this  method  of 
power  transmission,  the  parts  which  make  up  the  driving  shaft  are 
all  placed  in  a  straight  line  as  shown  in  the  lower  diagram  of  fig. 
31.  Another  construction  of  shaft  drive  is  illustrated  in  the  upper 
diagram  in  which  the  final  length  of  the  shafting  is  placed  at  an 
angle  with  the  other  portions.  This  necessitates  a  universal  joint 


38 


SELF-PROPELLED  VEHICLES. 


with  more  or  less  friction  and  wear  depending  upon  the  degree 
of  angularity  of  the  two  shaft  sections.  In  the  figure,  the  in- 
clination of  the  rear  section  is  somewhat  exaggerated  to  emphasize 
the  difference  in  construction. 

On  account  of  the  action  of  the  supporting  springs,  a  universal 
joint  is  necessary  as  the  shaft  sections  are  not  in  line  when  the 
car  is  light.  The  construction  is  such  that  when  the  car  is  loaded, 
the  propeller  shaft  is  in  direct  line  with  the  crank  shaft.  Under 
these  conditions  the  drive  is  accomplished  in  a  direct  line  which 
assures  the  delivery  of  the  maximum  possible  power  to  the  rear 
axle. 


FIG.  32.— Engine  and  Spur-drive  Connections  of  the  Stanley  Steam  Car- 
riage. The  engine  is  "direct-connected,"  driving  the  differential  through 
a  spur  gear.  A  vertical  strut  suspends  the  engine  from  the  body  of  the 
carriage. 

Spur  Gear  Transmissions. — Transmission  of  power  by  spur 
gears  is  in  very  many  respects  the  best  method  of  all.  The  drive 
between  spurs  is  steadier,  and  is  attended  by  smaller  loss  of  power 
than  between  bevels.  It  is  impracticable,  however,  in  connection 
with  designs  including  a  main  shaft  set  in  the  length  of  the 
frame,  bevels  being  necessary  to  change  the  direction  of  motion 
from  longitudinal  to  transverse  rotating  shafts. 


THE   DRIVING   GEAR. 


39 


Spur  gear  transmission  is  used  on  the  Stanley  car  as  shown  in 
fig.  32.  The  engine  is  placed  horizontally  in  such  a  position  that 
the  steel  gear  on  the  crank  shaft  of  the  engine  engages  the  main 
gear  of  the  differential,  thus  forming  a  direct  power  transmission. 


FIG.  33. — Friction  drive  of  the  Pittsburg  Truck.  Power  is  transmitted  by 
leather  fiber  cones  coming  into  contact  with  a  bevel  cast  iron  wheel. 
The  front  cone  gives  the  reverse  motion  to  the  truck,  the  inter- 
mediate cone  the  high  speed,  and  the  rear  cone  the  slow  speed. 

Although  with  well-designed  spurs  over  90  per  cent,  of  the 
delivered  power  of  the  engine  may  be  actually  transmitted  to  the 
driven  shaft,  the  spur  drive  will  admit  of  practically  no  interrup- 
tion of  full  engagement  between  the  teeth  by  thrusts  or  vibra- 


40 


SELF-PROPELLED   VEHICLES. 


tion.  Virtually  the  entire  efficiency  of  the  combination  depends 
on  maintaining  the  engagement  at  the  pitch  line.  If  spurs  are 
to  be  used  on  automobiles,  therefore,  it  follows  that  the  driven 
shaft  must  be  above  the  springs,  or  the  driving  shaft  below 
them.  The  latter  alternative  is  realized  in  electric  vehicles,  but 
the  former  depends  upon  some  such  arrangement  of  jointed 
axles  or  shafts  as  are  embodied  on  the  De  Dion  or  Thornycroft 
wagons.  The  famous  De  Dion  rear  axle  has  the  section  of  the 
shaft  carrying  the  differential  hung  above  the  springs,  and  con- 
nected to  the  road  wheels  by  universal  slip- joints,  as  shown  in 
the  figure.  The  Thornycroft  wagon  has  a  similar  slip-joint 
arrangement  on  a  counter-shaft,  arranged  to  afford  a  steady  drive 
from  the  engine  above  the  springs  to  the  driving  spur  in  mesh 


FIG.  34. — The  Haynes  Spur-gear  Transmission. 

with  the  driven  spur  on  the  axle  sleeve.  Such  devices  are  es- 
sential, in  order  to  maintain  a  steady  drive  between  the  meshing 
spurs  in  spite  of  the  rise  and  fall  of  the  springs. 

Haynes  Spur  Transmission. — A  device  formerly  used  on 
Haynes  carriages  accomplishes  the  end  of  an  uninterrupted  spur 
drive  with  nearly  the  same  efficiency  as  the  Thornycroft.  As 


THE.  DRIVING  GEAR. 


41 


shown  in  the  figure,  A  is  the  sprocket  fixed  at  one  end  of  the 
counter-shaft;  B,  a  turnbuckle  on  the  adjustable  distance  rod  be- 
tween the  first  counter-shaft  and  the  second  counter-shaft  carry- 
ing the  pinion,  C ;  C,  a  spur  pinion  keyed  to  the  second  counter- 
shaft, carrying  a  sprocket  driven  by  a  chain  from  A ;  D,  a  spur 
gear  on  the  rear  axle  meshing  with  spur  pinion,  C,  on  the  second 
counter-shaft ;  E,  a  rigid  distance  rod  for  maintaining  fixed  rela- 
tions between  the  spurs,  C  and  D.  The  advantages  of  this 
system  are  the  maintaining  of  a  steady  drive  without  the  usual 
wear  and  tear  on  the  moving  parts  consequent  on  sprocket  con- 
nections direct  from  the  first  counter-shaft,  or  from  the  main 
shaft  of  the  motor.  The  movements  of  the  distance  rod,  also, 
throws  no  strain  upon  the  springs,  as  in  many  other  forms  of 
transmission. 


FIG.  35. — The  Pierce-Racine  rear  axle  construction.  Pour  point  ball  bear- 
ings are  employed  throughout  as  shown  in  the  Illustration.  The 
bevel  pinion  shaft  has  an  inside  ball  bearing.  The  bevel  gear  hous- 
ing is  a  steel  casting  below,  with  an  aluminum  casting  cover.  The 
lower  gear  casing  member  has  full  circle  ends,  fixed  to  the  steel  axle 
casings  by  riveting  and  keying. 


CHAPTER  FIVE. 

THE  STEERING  OP  A  MOTOR  VEHICLE. 

Steering  Gear  of  Automobiles. — In  a  horse-drawn  vehicle, 
the  front  axle  shaft  is  centre-pivoted  below  the  body  of  the  car- 
riage and  in  turning  bears  on  the  "fifth  wheel."  Such  an  ar- 
rangement is  the  most  practical  for  this  class  of  vehicle,  since  the 
tractive  power,  the  horse,  can  pull  in  any  direction  without  the 
use  of  further  appliances  than  the  guiding  lines  or  reins.  In  motor 
vehicles,  since  the  motive  power  is  applied  to  the  rear  wheels, 
literally  pushing  the  structure  from  behind,  it  is  necessary  to 
provide  mechanical  means  for  shifting  the  direction  of  the  for- 
ward or  steering  wheels.  The  forward  axle  shaft  is  rigidly  se- 
cured across  the  body  of  the  vehicle,  and  has  no  movement  what- 
ever. At  each  end  it  carries  a  fork,  or  yoke,  to  which  is  bolted 
generally  at  right  angles  to  the  axle  shaft,  so  as  to  form  a  true 
knuckle-joint,  a  boss  carrying  two  branches,  one  of  them  coni- 
cal shape,  to  fit  the  axle  box  of  the  wheel,  which  is  suitably  se- 
cured, as  in  horse-drawn  vehicles,  so  as  to  rotate  freely ;  the  other 
being  an  arm,  shaped  for  attaching  the  transverse  steering  link 
bar.  This  link  bar  is  generally  arranged  to  connect  the  steering 
arms  of  both  stud  axles  on  the  through  axle  shaft,  the  connections 
for  the  control  handle  or  wheel,  placed  conveniently  to  the 
driver's  hand,  varying  with  different  designers. 

Pivoted  axles,  commonly  known  as  Ackerman  axles,  furnish 
the  readiest  and  simplest  means  for  steering  motor  vehicles,  at  the 
same  time  permitting  maintenance  of  stability.  The  transverse 
steering  link  bar  attached  to  an  arm  at  either  end  is  readily  ma- 
nipulated by  the  driver,  and  with  but  small  exertion,  since  the 
pivots,  attached  direct  to  the  axles  of  the  wheels,  permit  a  wide 
angle  of  variation  in  the  vehicle's  direction  of  travel  for  a  very 
slight  shifting  of  the  steering  wheel  or  handle.  The  balance  of 
leverage  being  also  in  the  driver's  favor,  it  is  possible  to  turn  the 
vehicle  in  any  desired  direction  quickly  and  with  ease. 

tt 


STEERING  A  MOTOR  VEH'lLLZ.  43 

The  Theory  of  Steering  Axles. — The  best  effect  of  pivoted 
steering  axles  depends  upon  fixing  the  steering  pivot  as  near  as 
possible  to  the  centre  of  the  road  wheel,  in  order  to  enable  the 
greatest  arc  of  operation  for  the  smallest  motion  of  the  hand.  In 
this  respect  the  steer  wheel  of  a  bicycle  is  typical,  and  some  light 
automobiles  having  the  wheels  similarly  mounted  on  forks  have 
been  notable  for  easy  and  efficient  operation.  But,  since  this 
construction  is  not  suitable  for  heavy  carriages,  designers  have 
busied  themselves  devising  other  methods  for  accomplishing  the 
same  result. 


FIG.    36. — A  Type  of  Stud  Steering  Axle,  showing  steering  arm  and  pivot  and 
plain  bearing  axle  and  box. 


1.  One  of  these  is  to  incline  the  stud  axle  downward  at  such  an 
angle  as  will  cause  the  tire,  or  periphery,  of  the  wheel  to  strike 
the  ground  at  a  point  coincident  with  a  line  drawn  through  the 
knuckle  pivot.    As  an  additional  advantage  for  this  construction, 
it  is  claimed  that  the  force  of  a  collision  is  delivered  at  or  about 
this  line  of  incidence,  rather  than  on  the  hub  or  its  axle  connec- 
tion, thus  ensuring  greater  security,  and  saving  the  driver  a 
shock. 

2.  Another  device  is  to  incline  the  pivot  axis  inward,  leaving 
the  axle  horizontal,  or  nearly  so,  with  the  result  that,  as  in  the 


44 


SELF-PROPELLED  VEHICLES. 


previous  case,  a  line  drawn  through  the  pivot  strikes  the  ground 
at  the  same  point  with  the  periphery  of  the  wheel  which  is  itself 
in  a  vertical  position. 

3.  Some  such  arrangements  as  the  Haynes  double  yoke  pivot 
may  be  used  with  good  effect.  In  this  device  one  yoke  is  of  a 
piece  with  the  through  axle  shaft,  the  other  pivot-bolted  at  each 
extremity  within  the  first,  and  carrying  the  axle  spindle  at  its  cen- 
tre. By  this  means  the  centre  of  the  steering  pivot  may  be 
brought  to  the  theoretically  correct  position  with  a  much  smaller 
rake  of  the  road  wheel  than  is  involved  in  the  first  device  men- 
tioned. 


FIG.  37.— Duryea's  Inwardly  Inclined  Steering  Pivot.  The  lines  passing 
through  the  pivot  and  across  the  axle  converge  to  the  point  of  contact  of  the  tire 
with  the  ground,  thus  securing  the  effect  of  centre  steering. 

4.  Several  attempts  have  been  made  to  place  the  steering  pivot 
precisely  at  the  theoretically  correct  point  by  use  of  a  hollow 
steering  hub  enclosing  the  pivot.  Of  these  the  Riker  hub  is  the 
best  known.  In  its  construction  a  hollow  steel  cylinder  is  pene- 
trated by  the  end  of  the  transverse  axle-tree  and  pivot  bolted  to 
it,  so  as  to  be  turned  in  either  direction  by  the  steering  arm,  H, 
fixed  at  its  inner  end.  Over  this  cylinder  the  wheel  hub,  also 
hollow,  is  slid  and  turns  upon  it  on  two  trains  of  ball  bearings. 


STEERING  A  MOTOR  VEHICLE. 


45 


The  Clubbe  and  Southey  Hub,  Fig.  40,  operates  on  a  simpler 
plan.  The  fork,  or  yoke,  on  the  through  axle  shaft  is  slightly 
bent  forward  at  the  end,  so  that  a  pivot  bolt  through  the  eyes 
pierces  a  boss  attached  tangent-wise  to  a  short  tubular  axle  bear- 
ing, in  which  the  stud  axle,  carrying  the  wheel,  revolves  freely. 
The  hub  is  hollow  and  hemispherical,  so  as  to  contain  the  whole 
mechanism  of  the  pivot  joint,  which  is  slightly  forward  of  the 
centre,  giving  a  caster  action  to  the  wheel  in  turning.  The  ad- 
vantage presumably  attained  in  this  caster  action  is  a  freer  and 
easier  shifting  of  direction  with  a  given  effort  at  the  steering 
wheel  or  lever. 


FIG.  38.— The  Haynes-Apperson  Double  Yoke  Steering  Pivot  Axle.  The  steer- 
Ing  arm  Is  attached  at  A,  thus  securing  the  turning  effect  at  approx- 
imately the  centre  of  the  wheel  hub. 

The  Arc  of  Steering. — To  achieve  the  end  of  positive  and  re- 
liable steering  effect,  it  is  necessary  that  the  steer  wheels  describe 
concentric  arcs  in  making  a  turn,  with  their  axle  bosses  on  radii 
from  a  common  centre,  differing  in  length  as  the  width  of  the 
vehicle.  This  involves  that  each  stud  axle  inclines  from  the 
straight-ahead  travel  line  at  an  angle  different  from  that  of  the 
other.  The  arcs  described  by  the  wheels  in  turning  must  be  con- 
centric, in  order  to  insure  continued  travel  in  the  desired  direc- 
tion, without  side-slip  or  harmful  resistance,  such  as  must  other- 


46  SELF-PROPELLED  VEHICLES. 

wise  result.  The  two  wheels,  having  the  same  diameter,  no 
matter  how  much  their  relative  speeds  may  differ,  will  by  any 
other  arrangement  fail  to  run  in  the  same  curved  direction. 

Turning  Arc  in  Railroad  Wheels. — The  same  principle  is  ap- 
plied in  railroad  cars  and  locomotives  in  a  manner  impracticable 
with  motor  carriages.  Here,  although  the  wheels  are  always 
rigidly  attached  in  pairs  at  either  extremity  of  rotating  through 
axles,  and  in  fours  to  the  trucks,  composed  of  two  parallel 
through  rotating  axles  with  their  attached  wheels,  the  differing 
concentric  arcs  described  by  the  two  rails  of  the  track  in  round- 


FIG.  39.— Hiker's  Pivoted  Steering  Hub.  A  is  the  axle  shaft;  B,  the  pivot 
connecting  A  to  the  tubular  swinging  hub,  C.  E  und  E'  are  annular 
cones  which  bear  on  the  balls  mounted  in  the  ball  races,  F  and  F', 
thus  permitting  the  hub  D  to  rotate  independently  on  the  inner  tube, 
C.  The  steering  arm,  H,  attached  to  C  turns  both  C  and  D  on  the 
pivot,  B. 

ing  a  curve  are  followed.  To  accomplish  the  desired  end,  rail- 
road car  wheels  are  made  with  a  cone-shaped  tread — a  double 
cone,  in  fact — the  base  being  against  the  flange  of  the  wheel.  In 
turning  a  curve,  then,  the  outer  wheel,  impelled  by  centrifugal 
force,  rotates  on  its  largest  diameter,  while  the  inner  wheel,  from 
the  same  cause,  rotates  on  its  smallest.  The  effect  approximated 
is  that  of  an  elongated  cone  whose  point  is  at  the  centre  of  the  arc 
of  turning,  and  its  base  on  the  periphery.  Thus  is  approximated 
the  theoretical  requirement  that  the  two  wheels  on  an  axle  should 
be  of  different  diameters  in  making  a  curve.  Since,  however,  the 
diameters  of  motor  carriage  wheels  may  not  be  varied  by  this  or 


STEERING  A  MOTOR  VEHICLE.  47 

any  other  means,  it  is  obvious  that  the  only  other  available  device 
is  such  a  variation  of  the  steering  angles  as  has  already  been 
mentioned. 

The  Steering  Wheels. — When  a  carriage's  travel  is  changed 
from  the  straight-ahead  direction  to  a  curve,  the  steering  wheel 
moving  on  the  in-track,  or  smaller  arc,  must  assume  a  greater 
angle  at  the  axle  than  the  outer  wheel,  which  moves  on  the  larger 
of  the  two  concentric  arcs.  It  is  evident,  moreover,  that  such 
variation  of  axial  angles  must  be  accomplished  by  some  device  at 


FIG.  40. — The  Clubbe  and  Southey  Pivoted  Steering  Hub.  As  may  be  seen, 
the  pivot  is  to  one  side  of  the  axle,  thus  giving  the  wheel  a  true  caster 
movement  in  turning.  See  Page  46. 

the  steering  arms  of  the  stud  axles.  If  these  steering  arms  be 
fixed  at  right  angles  to  the  axles,  so  that  the  transverse  drag-link 
is  of  a  length  theoretically  identical  with  the  distance  between  the 
wheel  treads,  any  effort  to  turn  the  wheels  in  steering  will  shift 
the  angles  of  both  arms  with  the  fixed  axle-tree  equally,  hence, 
causing  the  axles  to  assume  positions  as  radii  from  different 
centres.  The  result  will  be  that  the  outer  wheel  will  describe  an 
arc  tending  to  cross  those  described  by  all  the  other  wheels,  and 
may  slide  or  rub,  without  revolving,  as  much  as  one  foot  in  every 
six.  Such  a  procedure  must,  of  course,  retard  the  progress  of  the 
vehicle  very  seriously,  and,  from  the  uncertainty  of  steering  in- 
volved, must  be  particularly  troublesome,  even  dangerous,  on 
narrow  turns.  It  is  evident  in  this  case  that  the  -outer  wheel  axle 
is  at  too  great  an  angle,  or  that  the  inner  is  at  too  small  an  angle. 


48 


SELF-PROPELLED  VEHICLES. 


Steering  Constructions. — The  simplest  method  of  at  once  ob* 
viating  this  trouble  and  also  securing  the  proper  angles  of  the 
axles  is  to  incline  the  two  steering  arms  inward  from  the  right 
angle  and  make  the  transverse  drag-link  shorter  than  the  distance 
between  the  axle  pivots.  If  the  drag-link  be  in  front  of  the  axle- 
tree,  the  steering  arms  are  inclined  outward,  making  the  drag- 
link  longer  than  the  distance  between  axle  pivots. 

With  this  arrangement,  as  may  be  readily  understood,  any 
effort  to  change  the  direction  of  the  travel  will  cause  the  arm  of 
the  outer  wheel  to  approach  the  right  angle  with  the  transverse 
through  axle  bar,  and  cause  the  arm  of  the  inner  wheel  to  move 
proportionately  away  from  the  right  angle.  Moreover,  since  the 


FIG.  41.— Position  of  the  Wheels  of  a  Railroad  Car  on  the  Rails  In  Turning 
a  Curve,  showing  how  the  outer  and  inner  wheels  turn  on  different  di- 
ameters, thus  compensating  the  parallel  arcs  of  travel. 

end  of  the  transverse  drag-link  attached  to  this  inner  axle-arm 
must,  in  the  act  of  thus  widening  the  angle,  be  approached  nearer 
and  nearer  to  the  immovable  through  axle  bar,  it  must  describe 
an  arc,  thus  passing  through  a  greater  number  of  degrees  than 
will  the  opposite  or  outer  end.  Consequently,  the  object  of  se- 
curing a  greater  angular  inclination  for  the  axle  of  the  inner  wheel 
will  be  accomplished  and  the  proper  difference  for  all  usual  con- 
ditions between  the  angles  of  the  two  approximated.  That  is, 
although  it  generally  happens  that  the  angular  inclination  of  the 
steering  arms  works  best  on  curves  of  radii  midway  between 
the  extremely  long  and  extremely  short,  it  has  been  found  that 
the  difference  is  not  sufficiently  great  to  disturb  the  parallelism 
of  the  described  arcs  or  cause  damaging  slips  or  skidding  of  the 
rear  wheels. 


STEERING  A  MOTOR  VEHICLE. 


49 


The  Steering  Angle. — Generally,  the  steering  angle  of  a  motor 
carriage,  which  is  to  say  the  sum  of  the  inclinations  of  the  two 
steering  arms  from  the  right  angle,  is  between  fifty  and  sixty  de- 
grees, giving  an  inclination  for  each  arm  of  between  twenty-five 
and  thirty  degrees.  Some  of  the  best  makes  of  carriage  have  it 
at  or  about  twenty-five  degrees  for  each  arm.  As  shown  in  the 


FIG.  42.— Diagram  Illustrating  the  Position  of  the  Steering  Wheels  of  a 
Motor  Carriage  In  Turning.  As  will  be  seen,  they  both  are  tangential 
to  arcs  described  on  a  common  centre,  as  is  necessary  in  order  to  de- 
scribe such  concentric  arcs  and  give  positive  steering,  when  the  motive 
impulse  is  from  behind. 

accompanying  diagrams,  however,  various  designers  have  modi- 
fied the  typical  arrangement  of  inclining  the  steering  arms  in- 
ward and  using  a  drag-link  to  connect  them  by  such  devices  as : 

I.  Placing  the  arms  at  right  angles  and  using  a  link  in  two 
sections  connected  to  a  fork  or  bell  crank  having  the  total  re- 
quired angle,  fifty  or  sixty  degrees,  and  pivoted  at  the  centre  of 
the  fixed  axle  bar. 


50 


SELF-PROPELLED  VEHICLES 


2.  By  dividing  the  angle  betwen  the  centre-pivoted  bell  crank 
and  the  steering  arms,  making  the  former,  say  thirty  degrees  and 
the  two  latter  fifteen  degrees  each. 

The  primary  object  achieved  in  either  of  these  devices  is  to  en- 
sure the  end  of  ready  manipulation  of  the  steering  lever.  The 
first-named  construction  is  the  one  best  suited  to  carriages  hav- 
ing the  steering  pivot  in  the  theoretically  correct  place — within 


Co 


roo 


FIG.  43. 


o) 


FIG.  44. 


FIG.  45. 


FIGS.  43,  44  and  45. — Top  View  of  Motor  Carriage  Forward  Axles,  showing 
three  arrangements  of  link  bars  and  steering  arms.  In  the  first  the 
steering  arms  are  inclined  inward  at  the  required  angle  and  connected 
across  the  carriage  width  by  a  single  link.  In  the  second  the  steering 
arms  are  fixed  at  right  angles  to  the  axle-tree,  and  the  angle  of  inclina- 
tion is  made  at  a  centre  pivoted  bell  crank.  In  the  third  the  angle  of 
inclination  is  divided  between  the  steering  arms  and  the  central  bell 
crank.  Theoretically,  the  sum  of  the  angles  in  the  third  figure  is  equal 
to  that  in  the  first,  and  to  the  angle  of  the  bell  crank  in  the  second. 

the  hub.  When  for  structural  reasons  the  transverse  drag-link 
bar  is  placed  in  front  of  the  axle-tree,  a  position  preferred  by  sev- 
eral manufacturers,  the  steering  arms  attached  to  the  bosses  of 
the  swinging  axles  are  inclined  outward,  instead  of  inward,  at 
Mie  angles  found  most  suitable  with  reference  to  the  width  of  the 
vehicle  between  the  wheel  pivots  and  to  the  diameter  of  the 
wheels. 


STEERING  A  MOTOR  VEHICLE.  §\ 

The  construction  adopted  by  some  designers  of  inclining  the 
axle  stud  inward,  as  already  described,  achieves,  not  only  the 
very  desirable  end  of  centre-steering,  but  also  allows  a  certain 
inclination,  or  rake  to  the  steering  wheels,  as  in  a  bicycle,  when 
making  a  turn.  The  rake  is  a  positive  advantage  to  ready  steer- 
ing qualities,  when  the  inclination  of  the  axle  pivot  is  not  at 
so  great  an  angle  as  to  bring  unusual  side  strain  on  the  wheels. 
Other  things  being  equally  favorable,  it  is  also  efficient  in  re- 
ducing the  steering  effort. 

The  Center  of  Gravity  and  the  Wheel-base. — There  are  sev- 
eral questions  intimately  associated  with  the  problem  of  correct 
steering  angles.  Among  these  are  considerations  on  the  most 
reliable  means  for  avoiding  skidding  or  side-slip  of  both  rear  and 
front  wheels,  and  on  constructions  best  adapted  to  maintain 
balance  of  the  vehicle  in  making  short  turns.  The  progress  of 
motor  carriage  design  in  recent  years  has  established  the  prin- 
ciple that  a  low  center  of  gravity  is  a  necessity  in  high-speed  cars, 
in  order  to  avoid  the  tendency  to  overturn  at  a  sharp  inclination 
of  the  steering  wheels.  The  adjustment  of  the  center  of  gravity 
has  resulted  progressively  in  two  tendencies,  now  prevalent — the 
long  wheel-base  and  the  short  clearance  between  the  bottom  of  the 
car  and  the  ground.  Both  conduce  to  comfortable  riding  and 
immunity  from  overturning.  Side-slipping  is  also  avoided  in 
large  measure.  With  very  long  cars,  however,  difficulty  is  ex- 
perienced in  turning  sharp  corners,  or  in  steering  on  any  but 
easy  curves,  except  with  a  very  narrow  front.  These  matters 
will  be  explained  in  place. 

.  Skidding. — The  term,  "skidding,"  or  side-slipping,  as  gener- 
ally applied  in  motor  car  practice,  describes  the  occasional  ten- 
dency of  the  rear  wheels  to  slide  sideways  to  the  direction  of 
travel.  The  result  may  be  disastrous,  as  well  as  annoying,  since, 
in  the  event  of  colliding  with  a  large  or  immovable  obstacle  the 
wheel  may  be  broken  in  pieces,  or,  unless  the  center  of  gravity  is 
low,  the  vehicle  will  be  overturned.  The  same  term  is  also  ap- 
plied to  a  similar  behavior  in  the  front  wheels. 


83  SELF-PROPELLED  VEHICLES. 

According  to  authorities,  the  immediate  occasion  of  side-slip 
is  found  in  the  fact  that  under  certain  conditions  a  wheel  revolves 
more  rapidly  than  it  progresses,  or  progresses  more  rapidly 
than  it  revolves.  In  either  case  it  slides  over  the  road  surface, 
which  does  not  present  sufficient  adhesion  to  promote  traction, 


PlC.  46. — To  Illustrate  the  Inclination  of  wheels.  The  cut  shows  a  Mathe- 
son  car  having  the  front  wheels  inclined  three  degrees  to  balance  the 
"dishing"  of  the  spokes  and  bring  the  lowest  spoke  into  a  vertical 
position. 

or  the  balance  of  rotation  and  progression.  Particularly  when 
the  tread  of  the  tire  is  flattened  at  contact  with  the  ground,  as 
usually  happens  with  pneumatics,  the  loss  of  adhesion  results  in 
such  a  resolution  of  the  propelling  power  or  momentum  of  the 
vehicle  as  will  allow  of  motion  in  lateral  directions,  as  well  as 
straight  ahead. 


STEERING  A  MOTOR  VEHICLE.  £g 

Skidding  occurs  under  several  conditions : 

1.  When  the  brake  is  suddenly  thrown  in. 

2.  When  the  clutch  is  suddenly  thrown  in  or  out. 

3.  When  the  steering  gear  is  given  a  sudden  or  sharp  inclina- 
tion. 

As  may  be  readily  understood,  either  of  the  former  events 
tend  to  interrupt  the  balance  of  progress  and  rotation — hence 
cause  skidding.  However,  the  most  familiar  cause  is  found  in 
the  third  instance.  Any  inclination  of  the  steering  wheels  pro- 
duces a  side  pressure  on  all  the  wheels,  but  a  short  turn  is  par- 
ticularly liable  to  result  in  side-slip,  from  the  fact  that  the  pro- 
pelling power  and  momentum  continue  to  urge  the  vehicle  for- 
ward, leaving  a  large  part  of  the  active  energy  unresolved  into 
movement  on  the  arc  of  turning.  In  such  a  case,  also,  as  may 
be  readily  understood,  either  rotation  or  progression  is  the 
greater;  thus  adhesion  between  the  wheel  and  the  roadway  is 
lost. 

Protection  Against  Skidding. — Any  device  that  will  promote 
traction  will  lessen  skidding.  We  find,  therefore,  that  the  most 
effective  apparatus  to  this  end  are  those  that  enable  the  tire,  as 
it  were,  to  bite  into  the  road  surface,  rendering  difficult  sliding  or 
slipping  in  any  direction.  Such  are  net-works  of  rope  or  chain, 
hob-nailed  tire  covers,  and  conical  projections  molded  into  the 
rubber  of  the  tread.  In  addition  to  such  surface  precautions, 
there  are  important  considerations  in  the  design  and  balance  of 
the  vehicle  structure.  The  proper  location  of  the  center  of 
gravity  is  now  recognized  as  of  extreme  importance,  and,  par- 
ticularly in  very  long  vehicles,  also,  the  width  of  the  steering 
apparatus.  In  former  times,  when  designers  were  still  discussing 
the  proper  position  for  the  heaviest  weights  on  the  frame,  an 
overloaded  forward  axle  frequently  left  the  rear  wheels  so  lightly 
burdened  as  to  allow  the  vehicle  to  turn  end  for  end  on  a  greasy 
asphalt  street,  or  a  slight  inclination  of  the  steering  wheels.  At 
present  such  a  catastrophe  should  be  impossible  from  this  cause, 
on  account  of  better  distribution  of  the  load  and  the  use  of  long 
wheel-bases. 


04  SELF-PROPELLED  VEHICLES. 

Duryea's  Explanation. — Charles  E.  Duryea,  a  prominent 
American  automobile  authority,  gives  the  following  explanation 
of  the  matter: 

"  In  some  cases  skidding  is  caused  by  unequal  forces  at  the  rear  wheels. 
For  -example,  if  a  brake  is  applied  on  one  the  other  continues  to  force 
the  vehicle  forward  and  the  vehicle  tends  to  move  around  the  slowest 
wheel.  This  may  cause  skidding  of  the  front  end,  or  it  may  start  skidding 
at  the  rear  end.  If,  for  any  reason,  more  power  is  applied  to  one  rear 
wheel  than  to  the  other,  the  same  result  follows.  If  the  brakes  are  sud- 
denly applied  while  the  vehicle  is  being  turned,  the  wheels  may  start  sliding 
and,  once  started,  they  slide  sidewise  as  readily  as  any  other  direction,  so 
that  a  little  deviation  in  direction  of  the  steering  wheels  may  cause  the 
vehicle  to  skid.  It  is  readily  seen  that  a  change  of  direction  brings  the 
front  wheels  out  of  a  position  straight  ahead  and  causes  the  rear  end  to 
swing  sidewise  just  as  an  increased  resistance  on  one  front  wheel  would 
do.  Longer  wheel  base  lessens  skidding  by  decreasing  the  angle  between 
the  lines  through  the  centre,  and  to  one  of  the  forward  wheels.  The  gain 
by  increasing  the  length  of  the  wheel  base  is  not  nearly  so  pronounced  as 
that  by  narrowing  the  tread  of  the  front  wheels,  and  this  construction  is 
undo-'btedly  preferable.  While  rear  wheels  should  be  constructed  to  track 
witu  ordinary  carriages,  front  wheels  under  most  conditions  should  not, 
for  if  they  track  they  are  liable  to  refuse  to  come  out  of  wet  car  tracks, 
a're  almost  impossible  to  get  out  of  deep  ruts,  and  are  therefore  not  so  safe 
as  where  one  or  both,  because  of  difference  in  tread,  are  kept  out  of  the 
tracks  or  ruts.  The  only  objection  to  front  wheels  not  tracking  is  in  sandy 
roads,  where  the  depth  of  the  rut  will  cause  one  front  wheel  or  the  other 
to  skid  into  the  rut,  and  thus  swing  the  vehicle  diagonally  across  the 
road  in  its  attempt  to  move  forward." 

Analysis  of  the  Diagram. — Mr.  Duryea  explains  his  conten- 
tions by  the  accompanying  diagram : 

"Suppose  aa  to  represent  the  front  wheels  of  a  motor  vehicle,  bb, 
the  rear  wheels  and  c  the  centre  of  gravity.  If  either  front  wheel, 
a  meets  an  obstacle  throwing  an  increased  resistance  to  motion  on  that 
wheel  the  mass  of  the  vehicle,  acting  on  the  centre  of  gravity,  c,  together 
with  the  driving  power  on  the  rear  wheels  which,  in  effect,  are  pushing  c 
straight  forward,  will  tend  to  revolve  the  entire  vehicle ;  that  is  to  say, 
the  centre  of  gravity  c  around  a,  because  of  the  fact  that  a  line  through 
the  centre  of  gravity  c  in  the  direction  of  motion  passes  considerably 
to  the  side  of  a,  which  gives  rise  to  the  attempt  to  revolve  around  a. 
Suppose,  for  argument,  the  front  wheels  to  be  placed  at  dd,  it  will 
readily  be  seen  that  any  increased  resistance  on  one  front  wheel  tends  to 


STEERING  A  MOTOR  VEHICLE. 


55 


stop  that  corner  of  the  vehicle,  and  both  the  inertia  of  the  vehicle,  and 
the  push  on  the  rear  wheels,  carry  it  forward  and  sidewise;  or,  in  other 
words,  cause  it  to  skid.  This  effect  is  plain  with  the  exaggerated  position 
of  the  front  wheels  dd,  and  the  same  effect  although  less,  exists  with 
the  front  wheels  aa.  If,  however,  these  wheels  are  brought  close  to- 
gether, the  closer  the  better,  or  if  a  single  front  wheel,  e,  is  used,  the 
tendency  to  skid  is  very  much  reduced.  In  this  case  a  resistance  against 
the  front  wheel  is  met  directly  by  both  the  push  of  the  driving  wheels 
and  the  inertia  of  the  vehicle  and  no  tendency  to  skid  results. 


L-^ 

^  % 

>X  fl 

_.^^ 

N 

e   """**-> 

d                  "j 

\  / 

/? 

u 

/ 

1  /    \ 

/ 

I/    \ 

/ 

\ 

1 

t* 

\ 

\ 

j 

J 

fiG.  47.— Diagram  illustrating  Duryea's  explanation  of  the  influence  of  the 
wheel-base  on  steering  and  side-slipping. 

"Sometimes  instead  of  the  hind  wheels,  it  is  the  front  ones  that  skid, 
but  the  same  causes  act  to  produce  this.  For  example,  if  the  rear  wheels, 
bb,  refuse  to  slide,  the  increased  resistance,  such  as  snow,  mud  or  sand 
on  one  front  wheel,  d,  will  tend  to  swing  that  corner  of  the  vehicle  side- 
wise  out  of  its  path,  taking  the  other  wheel,  d,  with  it.  This  form  of 
skidding  is  particularly  found  on  roads  that  slope  to  one  side,  where 
one  outer  wheel  gets  in  the  gutter  and  slews  the  front  end  of  the  vehicle 
around.  It  is  no  less  dangerous  than  the  other,  although  less  seldom 
found.  The  exaggerated  diagram  makes  the  effect  plainly  apparent  and 
narrowing  the  wheels  betters  the  results  until  they  are  brought  together 
at  a  common  centre. 

"The  farther  to  the  rear  the  centre  of  gravity,  c,  is  located,  the  less 
the  angles  and  the  greater  the  immunity  from  skidding." 


66  SELF-PROPELLED  VEHICLES. 

The  Long  Wheel-Base  and  Steering. — Within  the  past  few 
years  the  safety  and  comfort  of  passengers  has  been  increas- 
ingly identified  with  the  long  wheel-base,  which  secures  the  de- 
sirable ends  of  a  low  center  of  gravity,  steadier  running  and 
reduced  danger  of  skidding,  and  is  variously  alleged  to  embody 
advantages  in  easier  steering.  That  the  latter  claim  holds  good 
on  long  turns  may  possibly  be  true;  that  it  is  not  the  case  on 
short  ones  is  readily  discovered.  The  following  explanation  from 
a  popular  authority  serves  very  well  to  explain  this  point : 

"When  intricate  manoeuvring  is  required,  and  on  rough  roads  generally, 
too  long  a  wheelbase  proves  objectionable.  In  the  first  place  it  is  found 
that  a  given  angle  of  the  wheels  will  not  produce  as  great  a  change  in 


FIG.  48.— Diagram    Illustrating1   the    effect    of   a   relatively   long   wheel-bas* 
on  the  turning  arc  of  a  motor  carriage. 

direction  when  the  wheelbase  is  long  as  when  it  is  short.  This  means 
harder  steering,  and  closer  attention  on  the  part  of  the  driver,  since  very 
sharp  turns  cannot  be  made,  and  must  be  avoided  by  long  sweeps,  com- 
mencing earlier  than  would  be  necessary  with  a  short  wheelbase.  When 
going  very  fast,  the  difficulty  is  much  magnified  and  great  watchfulness 
is  necessary  to  steer  a  desired  course. 

"In  going  around  a  curve  with  a  motor  car,  it  will  be  noticed  that  the 
rear  wheels  do  not  follow  in  the  tracks  of  the  front  wheels,  but  swing  con- 
siderably closer  to  the  inside  of  the  curve.  The  longer  the  wheelbase,  the 
greater  this  sidewise  displacement  of  the  rear  portion  of  the  vehicle,  and 
the  wider  the  space  occupied  by  the  car  while  making  the  turn.  Therefore, 
with  a  very  long  wheelbase,  a  narrow  road  in  many  cases  may  be  barely 
wide  enough  for  all  the  wheels  of  the  car  when  a  short  turn  is  made  on 
it,  and  passing  another  vehicle  may  be  decidedly  dangerous,  if  not  ab- 
solutely impossible.  ****** 


STEERING  A  MOTOR  VEHICLE. 


57 


"Perhaps  the  easiest  way  in  which  the  lay  reader  can  make  the  foregoing 
comparisons  between  long  wheelbases  and  short  wheelbases  clear  in  his 
mind  is  to  assume  the  cases  of  a  very  short  and  of  an  impossibly  long 
wheelbase. 

Thus,  with  a  wheelbase  only  a  foot  or  two  long,  it  is  evident  that  the 
steering  would  be  very  sharp  upon  the  least  movement  of  the  front  wheels, 
and  that  the  rear  wheels  would  follow  almost  in  the  track  of  them.  On  the 
other  hand,  with  a  wheelbase  one  hundred  feet  long,  it  clearly  would  be 
impossible  to  go  around  a  curve  on  an  average  road,  and  a  great  angle  of 
the  steering  wheels  would  be  necessary  to  produce  a  turn  even  of  wide 
radius.  Of  course,  these  are  exaggerated  examples,  but  they  serve  to 
suggest  an  idea  that  applies  very  definitely,  though  in  lesser  degree,  to 
wheelbases  ordinarily  long.  It  is  true  that  modern  cars  with  long  wheel- 
bases  usually  have  frames  much  narrower  in  the  front,  to  permit  of  turning 
the  steering  wheels  at  very  sharp  angles,  but  this  is  a  means  of  getting 
around  rather  than  of  doing  away  with  the  difficulty." 


Fic.  49. — Diagram  illustrating  a  straight  course  avoiding  sharp  turns  and 
side-slips  at  points  marked  by  crosses  (x  X  X  )•  Dotted  line,  course  to 
avoid;  straight  line,  best  course  to  follow. 

Avoiding  Side=SIip  in  Driving. — The  accompanying  diagram, 
borrowed  from  the  "Motorist's  Year  Book,"  exhibits  a  notable 
condition  in  which  side-slip  may  be  readily  incurred  and  avoided. 
The  explanation  of  the  diagram  is  as  follows : 

"At  each  of  the  points  marked  in  the  diagram  by  crosses,  if  the  road  is 
greasy  and  the  curves  abrupt,  the  motorist  will  stand  a  chance  of  side- 
slip. His  straight  road,  giving  no  opportunity  of  lateral  pressure  on  his 
wheels,  will  diminish  his  side-slip  risks  to  one,  the  last  curve  wherein  the 
road  is  shown  turning  off  at  a  sharp  angle.  This  he  must  take,  of  course, 
but  he  will  do  well  to  take  it  as  broadly  as  possible.  The  saving  of  tires 
by  such  a  method  is  surprising,  every  sharp  twist  and  turn  acting  de- 


58  SELF-PROPELLED  VEHICLES. 

structively,  according  to  its  angle  of  abruptness.  It  is,  of  course,  sup- 
posed that  the  driver  can  choose  his  route,  the  road  being  unfrequented, 
and  a  fair  outlook  obtainable,  conditions  to  be  found  over  miles  and  miles 
of  country  driving.  Where  there  is  traffic,  the  rule  of  the  road  must  be 
more  or  less  strictly  observed;  as  also  in  turning  corners,  beyond  which 
one  cannot  see. 

"In  climbing  hills,  again  the  automobilist  should  preserve  the  straightest 
possible  course.  A  horsed  vehicle  zig-zags,  in  order  to  spare  the  horse, 
by  making  the  wheels  act  laterally,  and  so  act  as  brakes  to  prevent  the 
backward  slipping  tendency  of  the  vehicle.  In  driving  a  car  the  practice 
is  different.  If  the  course  is  altered  the  front  wheels  exert  a  lateral 
pushing  action  on  the  road  surface  and  retard  the  car.  As  power  is  valu- 
able upon  hills,  it  should  never  be  wasted  in  turns,  abrupt  or  gentle,  if 
these  can  be  avoided." 

Wheel  and  Tiller  Steering. — The  steering  gear  of  a  motor 
carriage  is  controlled  by  a  tiller  or  hand  wheel  at  the  driver's 
hand.  The  difference  between  the  two  is  very  largely  a  matter 
of  design,  except  in  the  heavier  types  of  car;  since,  after  all,  the 
wheel  is  a  multiple  lever.  In  practice,  although  the  balance  of 
leverage  is  evidently  on  the  side  of  the  driver,  even  with  the 
simplest  form  of  steering  device,  the  advantages  of  the  wheel 
are  manifold.  With  the  best-designed  apparatus  to  neutralize 
vibration  and  prevent  any  outside  stress  from  reversing  the 
steering,  by  acting  to  change  the  direction  of  the  road  wheels, 
the  tiller  may  be  whipped  out  of  the  driver's  hand.  It  is  also 
tiring  to  hold  it,  even  in  the  straight-ahead  position,  while,  on 
making  a  turn,  a  large  arc  must  often  be  described.  With  a 
wheel  the  hands  may  always  rest  in  an  easy  and  natural  position, 
and  no  ordinary  shock  can  loosen  the  hold.  The  driver  always 
has  the  control  in  hand. 

Irreversible  Steering. — In  early  motor  carriages  the  steering 
tiller  or  wheel  was  connected  direct  to  the  axle  studs  by  arrange- 
ments closely  resembling  the  simple  steering  control  of  a  bicycle. 
The  result  was,  of  course,  an  immense  expenditure  of  strength  in 
effecting  changes  of  direction,  not  to  speak  of  constant  annoy- 
ance from  jolting  and  vibration,  and  the  danger  that  some  un- 
expected obstacle  would  whip  the  lever  from  the  hand.  The 


STEERING  A  MOTOR  VEHICLE. 


59 


necessity  of  devising  suitable  means  to  render  steering  irreversi- 
ble— which  is  to  say,  immune  from  interference  by  obstacles  act- 
ing on  the  road  wheels — was  very  early  recognized.  Typical 
methods  of  achieving  this  result  are  shown  in  accompanying 
diagrams.  In  all  of  these  the  neutralization  of  vibration  is  more 
or  less  successfully  combined  with  irreversibility. 


FIG.  50.— Steering  Arrangement  of  the  Clarkson-Capel  Steam  Wagon.  The 
spindle  of  the  steering  wheel  carries  a  screw  at  its  end,  which  works  a 
boss,  as  the  wheel  is  turned,  thus  actuating  the  lever  and  drag-link  at- 
tached to  the  arm  of  one  of  the  axle  pivots. 

The  Traveling  Nut. — The  simplest  arrangement  is  the  screw 
and  sliding  nut  device,  used  on  the  Clarkson-Capel  steam  wagon 
and  several  others.  In  this  device,  as  shown  in  the  figure,  the 
pillar  or  spindle  of  the  steering  wheel  is  threaded  at  its  lower 
end,  and  upon  it  a  hut  or  threaded  boss  is  let  on.  This  nut 
carries  a  lug  for  attaching  one  arm  of  a  fork  or  bell  crank,  whose 
other  arm  actuates  a  drag-link  working  on  the  steering  arm  of 
one  of  the  axle  studs.  When  the  steering  pillar  is  rotated,  the 
nut  is  caused  to  move  up  or  down  on  the  thread,  operating  the 
bell-crank  and  link  and  giving  an  inclination  to  the  road  wheels. 


60 


SELF-PROPELLED  VEHICLES. 


While,  as  may  be  plainly  seen,  the  inclination  thus  imparted  ta 
the  road  wheels  is  irreversible — since  the  gearing  connected  to 
the  sliding  boss  is  locked  in  any  given  position — there  can  be  no 
certain  freedom  from  vibration  at  the  hand  wheels. 

The  Worm  and  Sector. — In  the  second  type  of  steering  gear 
the  lower  end  of  the  steering  pillar  carries  a  worm  that  rotates 
a  toothed  sector.  On  the  spindle  of  this  sector  is  carried  an  arm 
that  actuates  the  steering  axles  through  a  drag-link  in  fashion 


FIG.  51.— Worm  and  sector  steering  device,  as  developed  by  Panhard-Levas- 
sor.  The  spindle  of  the  steering  hand  wheel  carries  a  worm  gear  at  its 
base,  which  actuates  a  toothed  sector,  as  shown.  This  swings  an  arm 
and  moves  the  drag-link  attached  to  the  arm  at  the  base  of  the  steering 
head.  The  transverse  drag-link  connecting  the  two  steering  heads  is 
attached  to  the  arm  extending  from  the  front  of  the  carriage.  The  link 
between  the  steering  head  and  the  sector  arm  has  ball  Joints  and  can 
adjust  the  distance  as  the  carriage  rises  and  falls  on  the  springs. 

similar  to  the  former  device.  Ball  joints  between  the  drag-link 
and  the  arms  at  either  end  enable  it  to  compensate  the  up-and- 
down  motion  o.f  the  springs.  Since  the  worm  can  actuate  the 
gear,  while  the  gear  cannot  actuate  the  worm,  this  type  of  steer- 
ing is  also  irreversible ;  although,  as  in  the  former  case,  vibration 
may  be  readily  imparted. 


STEERING  A  MOTOR  VEHICLE. 


61 


The  Traveling  Nut  and  Rack. — Combinations  of  the  two 
foregoing  types  of  steering  gear  have  been  produced  by  several 
designers.  In  one  of  these  the  worm  on  the  steering  pillar  causes 
a  threaded  boss  to  work  up  or  down,  as  in  the  first  type  of  ap- 
paratus. Instead,  however,  of  actuating  a  bell-crank,  it  carries 
a  rack,  which,  in  turn,  rotates  a  spur  pinion,  swinging  an  arm 
and  drag-link  in  the  manner  already  explained.  Others  have 
arranged  the  worm  and  threaded  boss,  with  its  rack  attachment, 
in  a  horizontal  position,  rotating  the  worm  shaft  through  bevel 
gears  from  the  steering  pillar.  Both  these  arrangements  are 
very  efficient  in  neutralizing  vibration. 


FIG.  52. — Combined  Nut  and  Rack  Steering  Gear;  a  device  embodying  a  high 
degree  of  immunity  from  back-lash  and  a  close  approximation  of  perfect 
irreversibility. 

FIG.  53.— Typical  Irreversible  Steering  Device;  a  spirally  grooved  gear  plate 
operating  a  sector. 

The  Gobron=BriIHe  Gear. — The  Gobron  steering  apparatus, 
used  on  the  French-built  motor  carriage  of  the  same  name,  is 
noteworthy  as  achieving  the  end  of  irreversible  steering  by  some- 
what different  means.  As  shown  in  the  accompanying  figures,  A 
is  a.  hand  wheel,  at  the  end  of  whose  spindle,  D,  is  an  arm,  E,  to 
which  is  pivoted  a  toothed  sector,  B.  The  arm,  E,  being  moved 
as  the  wheel,  A,  is  turned,  carries  around  with  it  the  pivot  of  the 
sector,  B.  This  sector  meshes  with  the  pinion,  C,  turning  loose 
on  the  steering  pillar,  as  shown,  and  is  accordingly  rotated 


SELF-PROPELLED  VEHICLES. 


through  an  arc.  Thus  the  arm,  F,  attached  to  the  pivot  of  B,  on 
E,  has  a  double  motion,  which  involves  that  the  slightest  move- 
ment of  the  wheels,  A,  is  unusually  effective  in  actuating  the  steer- 
ing arms,  through  the  link  attached,  as  indicated,  to  the  end  of 


Pio.  55. 
FIGS.  54  and  55.— The  Steering  Arrangement  of  the  Gobron-Brillie  Carriages. 

F.  Also,  any  stress  at  the  wheels  is  unable  to  reverse  or  disturb 
the  movement  thus  directed.  The  spring,  G,  attached  to  the  arm, 
H,  serves  to  steady  the  movement  and  restore  F  to  normal  posi- 
tion when  required. 


CHAPTER  SIX. 

COMBINED   STEERING   AND   DRIVING. 

Unusual  Steering  and  Driving  Devices. — The  standard,  and 
very  probably,  the  permanent  construction  for  an  automobile  is 
to  drive  to  the  rear  and  steer  on  the  forward  wheels.  However, 
numerous  alternate  constructions  have  been  attempted  at  various 
times;  some  proving  moderately  successful,  others  failing  out- 
right. These  may  be  divided  into  the  following  heads : 

1.  Front  driving  and  steering. 

2.  Front  driving  and  rear  steering. 

3.  Four-wheel  driving  and  front  steering. 

4.  Four-wheel  driving  and  four-wheel  steering. 

Front=wheel  Driving. — Front-wheel  driving,  as  embodied  in 
the  various  types  of  motor  wheels  and  fore-carriages,  so  common 
some  years  since  undoubtedly  originated  in  a  desire  to  adapt  horse 
carriages  to  motor-driving.  When  embodied  in  the  design  of 
motor  vehicles,  among  which  were  several  well-known  electric 
ca6s,  the  construction  was  undoubtedly  based  on  a  misapprehen- 
sion of  the  involved  conditions  of  automobile  operation.  In  both 
cases  the  error  arose  from  an  idea  that  horse-traction  was  thus 
imitated. 

Front-wheel  driving  involves  some  kind  of  device  for  combin- 
ing the  steering  and  driving  functions,  unless,  as  has  occasionally 
happened,  the  steering  is  on  the  rear  wheels.  Fig.  57,  showing  a 
combined  driving  and  steering  device,  as  used  in  some  of  the 
Hurtu  electric  cabs,  shows  one  arrangement  of  gearing  for  accom- 
plishing the  result.  Here  /  is  the  armature  of  the  motor,  NN,  the 
magnets  and  J3,  a  frame  supporting  the  armature  spindle  which 
rotates  on  the  axis,  XX.  To  this  spindle  is  attached  the  spur 
pinion,  P,  which  meshes  with  the  pinion,  r,  turning  on  the  axis, 
yy,  within  the  boss  of  the  steering  pivot.  The  spur  pinion,  rt  is 

88 


64 


SELF-PROPELLED  VEHICLES. 


made  in  one  piece  with  the  bevel  pinion,  a,  and  this  latter  engages 
the  toothed  bevel  ring,  b,  which  is  clamped  to  the  spokes  of  the 
wheel,  RR.  As  may  be  understood,  it  is  possible  to  swing  the 
wheel,  RR,  on  the  axis  j%  fixed  in  the  yoke,  Ey  without  inter- 


F.o.  57. 


Fio.  58. 


FIG.  57.— Motor  Steering  Wheel  of  the  Hurtu  Cabs.  A  drag-link  attached  to 
the  arm  of  the  pivots  can  turn  the  wheels  without  disturbing  the  opera- 
tion of  the  motor. 

FIG.  58.— Steering  Motor  Wheel  Arrangement,  by  which  a  worm  gear  and 
pinion  device,  actuated  as  shown  by  bevel  gears,  turns  the  stud  axle 
entirely  around  with  the  attached  motor  and  gearing,  without  inter- 
rupting a  steady  drive. 

fering  with  the  transmission  of  driving  power  from  the  pinion,  0, 
to  the  bevel  ring,  b,  thus  permitting  the  vehicle  to  be  steered  and 
driven  on  the  same  wheel.  Another  device,  shown  in  Fig.  58,  in- 
volves the  use  of  a  separate  axle  for  each  steering-driver. 

Front-driven  vehicles  travel  moderately  well  on  a  level  roadway, 
but  are  quite  useless  for  hill-climbing,  from  the  fact  that  the 
centre  of  gravity  is  thrown  so  far  back  of  the  engine  that  the 
front  wheels  tend  to  turn  without  progressing.  When,  on  the 


COMBINED    STEERING    AND    DRIVING. 


65 


other  hand,  the  rear  wheels  drive,  the  centre  of  gravity  falls  for- 
ward of  the  axle,  and  good  traction  is  possible. 

Tiller  and  Wheel  Steering. — In  the  earlier  motor  vehicles  the 
steering  wheels  were  controlled  by  a  lever  or  tiller  located  at  the 
dashboard  and  extending  toward  the  driver. 

In  steering  with  this  device  the  tiller  movement  is  in  the  reverse 
direction  to  that  taken  by  the  car.  This  presents  a  difficulty, 
which,  to  illustrate,  suppose  the  front  seat  passenger  stand  up 
for  any  reason  and  while  standing  to  accidentally  touch  the  tiller. 
The  immediate  effect  is  that  the  course  of  the  car  is  deflected  in 
the  opposite  direction  to  that  in  which  the  tiller  is  moved.  This 
may  cause  the  occupant  to  lose  his  balance  and  to  be  thrown 


Fro.  59. — Dynamics  In  Steering.  If  a  wheel  be  handled  by  its  lowermost  point,  it  acts 
like  a  til'er  anil  is  unsteady;  if  handled  by  its  uppermost  point  it  is  steady  at  all 
times.  Grasp'nsr  the  wheel  oppositely  with  both  hands  is  safe  for  steering  under 
all  road  conditions. 


against  the  tiller  with  such  force  that  the  car  would  make  a  very 
abrupt  turn  and  probably  upset. 

At  first  it  was  thought  the  general  principle  of  lever  or  tiller 
steering  was  at  fault.  In  point  of  fact,  it  is  the  direction  of 
the  steering  motion  that  is  dangerous;  reverse  the  tiller  motion 
to  correspond  with  the  direction  taken  by  the  car  and  the  forces, 
previously  a  cause  of  danger,  become  immediately  a  source  of  se- 
curity. 


66  SELF-PROPELLED  VEHICLES. 

In  steering  with  a  wheel,  the  manner  in  which  it  is  held  and 
handled  is  important.  Suppose  the  wheel  to  be  grasped  by  its 
lowermost  point  (fig.  59),  then  its  action  is  unsteady  like  that  of 
a  short  tiller.  Again,  suppose  the  wheel  to  be  handled  only  by  its 
uppermost  point,  the  motion  is  in  the  same  direction  as  the  car  is 
steered,  and  it  is,  therefore,  stable.  The  usual  method  of  hold- 
ing the  wheel,  is  to  grasp  it  in  both  hands,  one  on  each  side,  and 
when  steering  the  body  is  leaned  in  the  direction  in  which  the 
wheel  is  turned.  Hence,  if  the  driver  should  lean  over  further 
than  intended,  the  centrifugal  force  acting  on  the  driver's  body 
will  cause  it  to  sway  in  such  a  manner  that  equilibrium  will  be 
restored. 


PIG.  60. — An  example  of  rear  wheel  steering.  This  system  has  been  sup- 
planted by  front  wheel  steering,  because  when  a  carriage  is  standing 
near  a  curb,  it  is  impossible  to  turn  off  sharply,  as  the  steering  wheel 
(rear)  would  run  into  the  curb;  and  that,  when  near  a  ditch  or  im- 
passible section  of  the  road,  in  order  to  turn  away  from  these,  the 
steering  wheels  (rear)  must  first  run  toward  them,  which,  may  lead 
to  difficulties. 

Rear-Wheel  Steering. — The  objections  to  rear  steering  are 
that,  when  a  carriage  is  standing  near  a  curb,  it  is  impossible  to 
turn  off  sharply,  as  the  steering  wheel  (rear)  would  run  into  the 
curb  ;  and  that,  when  near  a  ditch  or  impassable  section  of  the 
road,  in  order  to  turn  away  from  these,  the  steering  wheels  (rear) 
tpust  first  run  toward  them,  which  may  lead  to  difficulties. 


CHAPTER  SEVEN. 


THE  SUPPORTS  OF   A   MOTOR  VEHICLE. 


Underframes  and  Springs. — A  few  years  ago  very  many 
automobiles  were  built  with  some  form  of  underframe,  whose 
essential  elements  were  perches  connecting  the  front  and  rear 
axles,  as  in  most  horse  carriages,  and  some  form  of  swivel  joint 
to  permit  of  considerable  distortion,  in  compensation  for  un- 
evenness  on  the  roadway.  The  two  objects  sought  in  this  sup- 
posedly necessary  structure  were  strength  and  flexibility.  Very 
many  designers  also  used  complicated  frameworks  of  steel  tubing, 
with  the  additional  object  of  securing  lightness.  These  elements 
have  now  been  almost  entirely  abandoned,  except  in  a  few  light 
steam  carriages  and  some  electric  wagons,  since  designers  have 
learned  by  experience  that  with  properly  arranged  springs  a 
motor  vehicle  can  be  strong  and  flexible,  without  perches  or 
swivels,  and  light,  without  steel  tubing. 

Advantages  of  an  Underframe. — In  one  very  essential  par- 
ticular, however,  the  underframe  was  a  desirable  complication. 
In  the  greater  number  of  cases  it  embodied  an  approximation  of 
the  essential  principle  of  three-point  support  for  the  body  and 
machinery,  which  is  not  always  perfectly  attained  in  more  re- 
cent constructions.  Thus,  the  typical  underframe  for  light  car- 
riages had  longitudinal  perches  converging  in  a  swivel  joint  at 
the  centre  of  the  forward  axle.  Others  had  two  such  perches 
s.wiveled  to  the  axle.  In  either  case  the  three-point  support  was 
partially  provided  under  conditions  involving  lateral  distortion  of 
the  running  gear,  in  spite  of  the  inevitable  stiffness  of  all  such 
frames  and  the  indifferent  efficiency  of  the  swivel  joints. 

or 


68  SELF  PROPELLED  VEHICLES. 

Three= Point  Support. — Three-point  support  is  desirable  from 
the  fact  that,  whatever  the  strain  and  distortion  encountered,  the 
three  points  always  fall  in  one  plane.  If  an  object  rests  evenly 
upon  four  points,  it  is  evident  that  any  force  acting  to  remove 
one  of  the  supports  tends  to  destroy  the  stability  and  throw  the 
body  into  a  plane  at  an  angle  with  the  plane  of  the  other  three 
supports.  If,  on  the  other  hand,  its  weight  be  evenly  distrib- 
uted between  three  points,  it  is  adequately  supported  on  any 


FlG.  61. — Marmon  Double  Three-Point  Support. 

plane,  and  a  force,  acting  unduly  on  one  of  the  points,  cannot 
draw  away  the  support — rather  drawing  the  supported  body  in 
the  direction  of  its  moving  stress. 

One  of  the  most  notable  applications  of  the  principle  of  three- 
point  support  is  found  in  the  Marmon  car.  Here  a  triangular 
under  frame  is  swivelled  around  the  propeller  shaft  at  the  rear 
and  supported  on  the  elliptical  springs  over  the  front  axle.  The 
body  frame  is  supported  over  the  rear  springs,  and  swivelled  to 
the  base  of  the  triangular  under  frame  at  the  front.  This  arrange- 
ment assumes  the  horizontal  position  of  the  engine  and  body,  no 
matter  what  obstructions  are  encountered  by  the  wheels. 


Three-Wheel  Carriages. — From  such  facts  we  are  able  to  ap- 
prehend the  logical  force  behind  some  of  the  leading  arguments 


SUPPORTS  OF  A  MOTOR  VEHICLE.  69 

for  the  three-wheeled  carriage.  As  already  suggested  in  a  former 
chapter,  it  embodies  the  theoretical  requirements  of  easy  steer- 
ing, and,  contrary  to  first  supposition,  is  less  easily  upset.  Charles 
E.  Duryea,  the  leading  advocate  of  this  type  of  vehicle,  says: 

"The  future  popular  two-passenger  carriage  will  be  a  three-wheeler, 
because  of  the  many  advantages  which  only  need  to  be  known  to  be  appre- 
ciated. *****  The  three-wheeled  carriage,  if  properly  designed, 
rides  as  easy  as  a  four-wheeler,  or  so  nearly  so  that  the  difference  cannot 
be  told  by  a  blindfolded  observer  riding  in  the  two  alternately;  while  the 
three-wheeler  steers  more  easily,  requires  less  power  to  propel,  starts  and 
stops  more  quickly,  is  simpler,  lighter,  very  much  better  in  mud  and  appre- 
ciably better  everywhere  else." 

Commenting  on  the  bicycle  traditions,  formerly  prominent  in 
automobile  construction,  Mr.  Duryea  says  again : 

"Engineers  make  a  mistake  who  attempt  to  apply  their  experience  in- 
discriminately to  carriages,  for  the  carriage  problem  is  not  a  single-plane 
problem.  Both  the  cycle  and  its  wheels  receive  strains,  and  in  a  single 
plane,  while  cycle  riders  save  themselves  and  the  machine  by  standing  on 
the  pedals  on  rough  spots.  The  automobile  rider  never  does  this,  while 
the  constant  torsions  and  wrenchings  of  a  four-cornered  frame  are  simply 
indescribable. 

The  Chassis  and  Springs. — At  the  present  day  light  carriages 
are  most  often  constructed  with  long  side-spring  perches  be- 
tween the  axles  and  have  the  body  supported  on  a  flat  frame 
midway  in  their  length.  "With  heavy  carriages  the  body  rests  on 
a  rectangular  framework  of  iron  or  steel  that  is  directly  sup- 
ported on  the  springs  attached  to  front  and  rear  axles,  forming 
the  "chassis,"  or  running  gear.  With  either  construction  com- 
pensation of  different  levels  is  possible,  as  in  riding  along  the 
side  of  a  slope  or  going  over  a  rock  in  one  of  the  wheel  tracks, 
the  springs  serving  the  double  purpose  of  absorbing  the  jars  of 
travel  and  giving  the  running  gear  a  necessary  degree  of  dis- 
tortability. 

Construction  of  Springs. — The  leaf  springs  used  in  road  car- 
riages and  railroad  cars  consist  of  several  layers  of  steel  plates  or 


70  SELF-PROPELLED  VEHICLES. 

leaves  more  often  slightly  bent,  so  that,  when  laid  together,  they 
are  found  forming  superposed  arcs  of  so  many  concentric  circles. 
It  is  essential  to  a  serviceable  spring  of  this  description  that  the 
line  of  the  arc  be  carefully  followed  from  end  to  end  of  each 
plate,  and  that  no  attempt  be  made  to  straighten  or  bend  back 
the  extremities  of  the  longest  leaves.  This  is  true  because  the 
spring  effect  is  derived  from  the  temper  of  the  metal  in  permitting 
the  load  to  flatten  all  the  arcs  at  once  under  a  single  stress,  which 


FIG    62.,— Three-point  suspended  spring,  or  platform  spring^  one  of  the  latest  and 
most  conspicuous  improvements  in  spring  suspension  designs. 


involves  that  they  should  slide  upon  one  another  in  altering  their 
shape,  as  could  not  be  the  case  were  there  any  such  departure 
from  the  line  of  the  arc,  as  has  been  mentioned.  In  that  case 
the  several  plates  would  tend  to  separate  and  "gape"  under  a 
load  requiring  a  degree  of  compression  tending  to  bring  the  ex- 
tremity of  any  arc  to  the  straight  portion  of  the  top  leaves.  The 
result  would  be  a  loss  in  spring  action,  and  a  probable  source  of 
breakage  on  occasion. 

The  Construction  of  Springs. — In  constructing  laminated 
leaf  springs  it  is  essential  that  the  plates  should  decrease  on  a 
regular  scale  of  lengths,  in  order  that  the  structure  may  be  of 
equal  strength  throughout  and  of  sufficient  flexibility  for  the  loads 
calculated  to  its  dimensions.  Where  such  a  spring  is  thick,  con- 
sisting of  a  number  of  plates,  it  is  a  good  working  rule  that  the 
ends  of  each  several  plates  should  touch  the  sides  of  a  triangle, 


SUPPORTS  OF  A  MOTOR  VEHICLE. 


71 


whose  base  is  drawn  between  the  extremities  of  the  longest  plate 
and  whose  apex  is  at  or  about  the  theoretical  centre  point  of  the 
spring's  movement.  This  means  that,  with  a  well-proportioned 
spring  in  its  normal  shape,  the  end  of  each  separate  plate  should 
be  equidistant  from  that  of  the  one  immediately  above  it  and  of 
the  one  immediately  below  it.  By  this  construction  even  dis- 
tribution of  stress  is  attained  without  waste  or  resistance  from 
inactive  portions  of  the  length  of  each  plate,  as  would  be  the  case 
in  a  laminated  spring  flattened  at  the  top  plate  and  having  the 
longitudinal  profile  shaped  to  an  arc.  Such  a  spring,  however, 


Fie.  63.— Semi-elliptical  Spring  and  Radius  Rod  of  the  Mors  Cars.  The  rod, 
A,  maintains  a  fixed  distance  between  the  sprocket  pinion,  B,  and  the 
wheel  axle,  C,  even  when  the  springs  are  constantly  in  action.  This 
carriage  also  has  a  device  for  varying  the  distance  between  the  counter- 
shaft at  B,  and  the  engine  pulley,  by  sliding  the  entire  shaft  forward 
or  back  under  impulse  from  the  screw,  D.  The  spring,  being  hung  on 
links  at  front  and  rear,  has  considerable  play,  up  and  down,  without 
disturbing  the  fixed  relation  of  the  axle,  C,  and  the  countershaft,  B, 
as  determined  by  the  radius  rod,  A. 


would  embody  bad  construction  in  another  particular,  since  it 
would  neglect  one  very  essential  feature  of  spring  construction — 
curvature  of  the  plates.  This  curvature  is  intended  to  represent 
the  difference  between  the  spring  under  static  and  maximum 
load ;  at  the  latter  point  its  leaves  should  be  nearly  straightened 
under  stress;  beyond  that  point,  as  they  are  bent  backward  and 
downward,  the  point  of  ultimate  strength,  involving  loss  of  elas- 
ticity and  breakage,  is  rapidly  approached.  It  follows,  therefore, 
that  the  end  of  a  perfectly  elastic  and  serviceable  spring  is  best  at- 
tained by  such  curvature  as  will  allow  bending  of  the  plates  from 
each  extremity  of  the  top  plates,  on  the  support  at  the  centre, 


72  SELF-PROPELLED  VEHICLES. 

without  involving  endwise  compression,  as  is  the  case  when  the 
curve  approaches  a  semi-circular  contour.  Consequently,  lami- 
nated leaf  springs  are  usually  constructed  to  an  arc  of  never 
more  than  ninety  degrees  and  often  very  much  less. 

According  to  arrangement,  there  are  three  varieties  of  leaf 
spring  used  on  automobiles :  elliptical,  semi-elliptical  and  scroll. 

THE  SEMI-ELLIPTICAL  SPRING  consists  of  a  segment  formed  by 
a  number  of  leaves  or  blades,  and  is  arranged  to  be  attached  at 
the  bottom  and  the  two  extremities  of  the  arc. 


FIG.  64. — Scroll-elliptic  Rear  Axle  Rear  Spring  used  on  models  of  the  Pack- 
ard Light  Car..  The  C-shaped  upper  portion  is  connected  by  shackles 
to  the  elliptical  lower  half,  the  effect  being  to  allow  the  use  of  fixed 
distance  rods  and  keep  the  chain  taut,  without  the  use  of  the  usual  de- 
vices of  foreign  and  American  carriages. 


THE  ELLIPTICAL,  SPRING  is  formed  by  connecting  two  semi- 
elliptics  or  arc-shaped  springs  at  their  extremities — generally 
by  bolts  passed  through  perforated  bosses  formed  at  the  ex- 
tremities of  the  longest  leaves — and  is  attached  at  the  apex  of 
each  arc  by  clips  or  nuts. 

THE  SCROLL  SPRING  differs  from  the  semi-elliptic  in  having 
one  extremity  of  the  arc  rolled  up  and  turned  inward.  It  may 
be  attached  by  a  link  or  a  shackle  to  a  flat  or  semi-elliptical  spring 
— forming  a  "scroll-elliptic" — or  to  the  body  suspended  above 
the  axle. 

Springs  on  Motor  Carriages. — We  may  readily  understand 
that  motor  carriages,  being  intended  primarily  for  high  rates  of 
speed,  involve  spring  conditions  found  in  neither  horse-drawn 
vehicles  nor  railroad  cars.  The  latter,  although  traveling  at 
speeds  often  100  per  cent,  greater  than  the  average  automobile, 


SUPPORTS  OF  A  MOTOR  VEHICLE.  73 

run  upon  an  even  and  comparatively  unresistant  roadway — the 
track  of  steel  rails — while  the  former,  although  built  for  the  ordi- 
nary highways,  as  are  automobiles,  are  seldom  calculated  for  any 
but  very  moderate  rates  of  speed.  Railroad  cars  must  thus  pro- 
vide against  a  maximum  speed,  with  a  minimum  road  roughness 
and  resistance;  horse  carriages,  on  the  other  hand,  must  provide 
against  maximum  roughness  and  resistance  with  minimum  speed ; 
motor  carriages  must  be  able  to  attain  high  speeds  and,  at  the 
same  time,  resist  the  annoying  and  destructive  effects  of  road- 
ways, inevitably  irregular  as  to  resistance  and  other  conditions 


FIG.  65.— Scroll   Bottom   Carriage  Spring,   half  elliptic,   showing  connections 
by  links  and  shackles. 

of  surface.  As  a  general  proposition,  therefore,  we  may  assert 
that  such  springs  as  will  promote  comfort  will  prevent  undue 
wear  and  tear  on  the  motor  and  parts,  which,  in  fact,  makes  the 
end  of  easy  riding  for  the  passengers  the  prime  consideration. 

Resistance  and  Resilience. — To  be  thoroughly  serviceable, 
a  spring  should  possess  two  essential  qualities  in  due  propor- 
tion: resistance  and  resilience.  While  a  spring  should  be  cal- 
culated to  give  sufficiently  to  absorb  the  jars  of  travel,  it  should 
not  be  so  resilient  as  to  rebound  with  a  series  of  oscillations. 
This  produces  a  movement  that  is  liable  to  be  extremely  annoy- 
ing, while,  at  the  same  time,  contributing  nothing  to  protecting 
the  mechanism.  As  a  good  general  rule,  the  best  spring  is  one 
that  "moves  quickly,  when  idle  or  worked  on,  and  slowly,  when 
working";  that  is  to  say,  one  that  absorbs  jars  by  friction  be- 
tween its  leaves,  rather  than  transforming  them  into  a  series  of 
jumps.  The  '  'happy  mean, ' '  therefore,  lies  between  the  extremes 
of  over-sensitiveness  and  over-rigidity 


74 


SELF-PROPELLED  VEHICLES. 


The  Action  of  Springs. — In  this  connection  it  is  desirable  to 
remark  that  good  spring  action  can  be  obtained  only  with  springs 
adapted  by  weight  and  elasticity  for  the  work  required  in  any 
given  case.  The  efficiency  of  a  spring  can  never  be  increased 
by  oiling  between  the  leaves,  since  it  will  not  give,  except  under 
sufficient  load,  and,  even  then,  the  friction  of  each  leaf  upon  its 
neighbor  is  an  essential  part  in  the  work  of  absorbing  jars.  As 
some  writers  have  expressed  it,  the  jars  of  travel  are  trans- 
formed into  heat  by  this  friction.  At  the  same  time  the  danger 
that  it  will  wear  out  the  spring  is  exceedingly  remote. 


PIG.  68. — Double  semi-elliptical  spring  attachments  used  on  some  electric 
vehicles.  The  body,  being  suspended  entirely  by  links  on  the  extremities 
of  the  springs,  has  the  full  benefit  of  spring  action. 

Considerations  in  Spring  Design. — Apart  from  certain  well 
ascertained  figures  on  the  static  weight  of  the  load  and  the  size 
and  tensile  strength  of  the  springs  designed  to  carry  it,  there  are 
no  reliable  data  regarding  the  proper  proportions  of  springs  for 
automobile  carriages.  As  we  have  said,  this  is  and  must  con- 
tinue a  matter  to  be  governed  most  largely  by  experiment,  apart 
from  mathematical  calculations,  since  the  constantly  varying  con- 
ditions of  automobile  travel  preclude  exact  theory.  Among  these 
variants  may  be  mentioned  high  speeds  on  any  and  every  kind  of 
road  and  the  use  of  pneumatic  tires.  The  matter  is  still  further 
qualified  by  the  size  of  the  tires  and  the  degree  of  inflation,  for 
both  of  these  points  are  important  in  modifying  the  stress  to 


SUPPORTS  OF  A  MOTOR  VEHICLE.  75 

come  upon  the  springs.  Indeed,  there  is  no  more  important 
factor  in  the  high-speed  motor  vehicles  than  the  rubber  tires,  al- 
though the  properties  developed  in  its  practical  operation  by  no 
means  permit  its  use  on  vehicles  without  suspension  springs  of 
some  description. 

The  Effects  of  Pneumatic  Tires. — The  use  of  pneumatic 
tires  on  a  vehicle  permits  the  absorption  of  considerable  vibration 
and  the  consequent  use  of  softer  springs  than  are  possible  with 


FIG.  67. — Forward  running  gear  of  the  Northern  Car,  showing  springs 
connected  with  a  vertical  shackle.  With  this  arrangement,  it  is 
claimed  the  return  of  the  spring  will  be  confined  to  the  power  of  its 
tension  or  deflected  state.  It  must  return  through  the  shackle  on 
dead  center,  as  it  were,  and  not  through  the  shackle  as  a  hinge. 

steel  tires.  The  bouncing  motion,  frequently  developed  by 
pneumatic  tires  is  neutralized  by  the  use  of  properly  adjusted 
springs,  although  in  the  matter  of  adjustment  we  must  calculate 


76  SELF-PROPELLED  VEHICLES. 

as  essential  elements  the  size  and  degree  of  inflation  of  the  tires, 
the  weight  and  dimensions  of  the  springs,  and  the  average  speed 
used.  In  some  respects  a  heavier  spring  gives  easier  riding  than 
a  light  one,  since  "he  latter  is  apt  to  bounce  disproportionately, 
even  with  good  jneumatic  tires,  when  the  road  is  somewhat 
rough. 

Condition  of  Spring  Dimensions. — In  judging  of  the  dimen- 
sions and  elasticity  of  springs  suitable  for  carriage  use,  the  limit 
of  elasticity  must  be  carefully  considered  with  relation  to  the 
static  and  maximum  loads  to  be  carried  by  the  vehicle. 

THE  STATIC  LOAD  is  the  dead  weight  of  the  vehicle  body  and 
frame,  together  with  that  of  the  passengers  and  other  freight, 
estimated  when  at  rest. 

THE  MAXIMUM  LOAD  is  the  proportionately  increased  weight 
of  the  same  items,  with  relation  to  the  traction  effort  required 
when  the  vehicle  is  running  at  its  highest  speed,  under  test  con- 
ditions as  to  road  roughness  or  hill-climbing  requirements. 

THE  ULTIMATE  LOAD  is  the  greatest  weight  possibly  carried 
with  good  spring  action ;  the  limit  of  the  spring's  endurance. 

That  the  springs  should  be  calculated  to  retain  the  elasticity, 
or  have  the  ultimate  strength  far  beyond  the  maximum  load,  is 
obvious,  when  we  consider  the  office  of  a  spring.  In  calculating 
the  proportions  of  springs  in  the  best  constructed  railroads,  it  is 
usually  customary  to  consider  the  maximum  load  as  twice  the 
static  load.  Whence  it  is  the  general  practice  to  estimate  the  fit- 
ness of  a  given  spring  for  its  work  as  equivalent  to  the  quotient 
of  the  weight  of  the  spring  divided  by  the  product  of  its  length, 
between  the  extremities  of  the  longest  leaf,  and  the  number, 
width  and  thickness  of  the  other  several  leaves. 

Proportionate  Loads. — The  variable  nature  of  carriage  roads 
makes  the  proportion  of  static  and  maximum  load  much  higher 
for  horse-drawn  vehicles  than  for  railway  cars,  except  where 


SUPPORTS  OF  A  MOTOR  VEHICLE.  77 

only  the  most  moderate  speeds  are  to  be  used ;  but  for  automobiles 
always  calculated  for  high  speeds,  it  never  falls  below  a  ratio 
of  i  to  3,  and  is  often  estimated  as  high  as  I  to  5. 

Adjusting  Weights. — As  has  been  pointed  out  by  several 
authorities,  the  difficulty  of  obtaining  springs  for  automobiles, 
A-hich  shall  be  serviceable  under  all  conditions,  is  greatly  in- 
creased when  the  weight  of  the  body,  motors,  etc.,  is  very  much 
in  excess  of  that  of  the  passengers  provided  for.  This  is  true, 
since  a  spring  that  will  subserve  the  end  of  easy  riding  under 
usual  conditions,  with  extra  heavy  accessories  of  this  descrip- 
tion, would  permit  no  end  of  jolting  and  annoying  vibration  at 
high  speeds  on  imperfect  roads.  The  fault  is  difficult  to  discover 
except  under  test  conditions. 

Placing  Springs. — To  sum  up  the  general  requirements  in  a 
few  words,  we  may  say  that,  while  pneumatic  tires  will  absorb 
very  many  vibrations,  thus  permitting  soft  and  light  springs  under 
the  body,  the  occasional  inequalities  in  the  road  are  liable  to  occa- 
sion a  quick  succession  of  annoying  jolts,  reaching  by  accumu- 
lated forces  almost  to  the  limit  of  spring  elasticity,  or  succeed- 
ing one  another  so  rapidly,  at  high  speed,  that  the  springs  have 
little  time  to  recover  their  normal  shape.  This  seems  to  indicate 
that  a  heavier  spring  is  preferable,  or  else  that  spring  construc- 
tion must  be  in  some  way  varied  to  give  firmer  attachments  and 
more  evenly  distributed  elasticity;  the  time  required  by  the 
spring  to  recover  itself  being  the  same  under  all  conditions,  some 
springs  are  thus  unfit  for  high  speed  work.  Many  manufac- 
turers prefer  semi-elliptical  springs  to  the  full  elliptical,  on  the 
ground  that  their  elasticity  is  greater  for  a  given  weight  of  spring, 
and  the  consensus  of  opinion  on  the  latter  is  that  the  longer  the 
spring,  within  reasonable  limits,  the  greater  the  combined  elas- 
ticity and  lightness.  When  such  springs  are  used  as  side  sup- 
ports it  is  general  practice  to  attach  one  end  direct  to  the  longi- 
tudinal frame  and  connect  the  other  by  a  link,  thus  allowing  am- 
ple freedom  toward  lengthening.  When  placed  transversely  over 


78 


SELF-PROPELLED    VEHICLES. 


the  forward  axle  both  ends  are  secured  to  links,  the  centre  being 
securely  clamped. 

Rules  for  Calculating  Springs. — As  a  general  proposition, 
the  usefulness  of  a  spring  for  given  work  and  load  is  largely  a 
consideration  of  the  total  length  of  the  structure  between  points 
of  attachment.  However,  the  thickness  and  number  of  the  leaves, 
and  the  quality  of  the  steel  used — the  last-named  consideration  is 
of  the  utmost  importance — enter  into  the  formulae  followed  in 
railroad  work  and  carriage  designing.  These  same  formulae  are 
useful  to  the  automobile  builder.  They  may  be  summarized  as 
follows : 


FIGS  68  and  69.—  Diagrams  illustrating  the  forward  and  sidewise  lunges  of 
the  body  of  a  motor  carriage  in  travel,  with  indication  of  the  distor- 
tion of  elliptical  springs.  See  Page  82. 

Let  B  represent  the  breadth  of  the  plates  in  inches. 
Let  T  represent  the  thickness  of  each  in  sixteenths  of  an  inch. 
Let  N  represent  the  number  of  plates  in  the  spring. 
Let   S  represent  the  working  span,  or  the  distance  between 
the  centres  of  the  spring  hangers,  when  the  spring  is  loaded. 
Let  W  represent  the  working  strength  of  a  given  spring. 
Let  E  represent  the  elasticity  of  the  spring  in  inches  per  ton. 

THE  ELASTICITY  OR  DEFLECTION  of  a  given  spring  is  found  by 
the  following  formula  : 


1.66 


N  B  T3 


=  E  in  1  6th  inch  per  ton  load. 


Other  authorities  give  the  formula : 
S3 


CNBT3 


=  E  in  inches  per  ton  load. 


SUPPORTS  OF  A  MOTOR  VEHICLE. 


79 


Here  C  represents  the  constant  40,000  for  single  and  20,000 
for  double  springs,  and  T,  the  thickness  of  each  plate  in  inches 
or  fractions  of  an  inch. 

THE  SPAN  LENGTH  due  to  a  given  elasticity  and  number  and 
size  of  plates  is  as  follows : 

3 

E  B  N  TS    =  S  in  inches. 

1.66 


FIG.  70. — The  Rainier  Pedestal  Frame,   designed  to  control   the  movement  of 
elliptical  springs,  preventing  all  distortions  in  travel. 


THE  NUMBER  OF  PLATES  due  to  a  given  elasticity,  span  and  size 
of  plates: 

S3  x  i .  66  =  N 
KBT3 

THE  WORKING  STRENGTH,  or  greatest  weight  a  spring  can  bear, 
is  determined  as  follows: 

B  T2  N 

Q-  =  W  in  tons  (2,240  Ibs.)  burden. 

THE  SPAN  DUE  TO  A  GIVEN  STRENGTH,  and  number  and  size  <W 
plates : 

BT*  N 

— =r  =  S  in  inches. 


80  SELF-PROPELLED  VEHICLES. 

THE  NUMBER  OF  PLATES  suited  to  a  given  strength,  span  and 
size  of  plates : 

"•3WS 
BT2  N> 


The  Cut=and=Try  Method. — A  prominent  American  manufac- 
turer of  carriage  springs,  the  Tuthill  Spring  Co.,  underrates  the 
value  of  formulae  like  the  above,  insisting  that  experiment  alone 
can  completely  solve  the  matter.  They  make  the  carrying  ca- 
pacity of  a  spring  dependent  upon  the  following  conditions: 

1.  Upon  the  length  of  the  spring,  because  a  longer  spring  is 
limberer  than  a  shorter  spring. 

2.  Upon  the  width  of  the  steel,  a  wider  one  being  stiffer  than 
a  narrower  one. 

3.  Upon  the  number  of  plates,  more  plates  being  stiffer  than 
fewer  plates. 

4.  Upon  the  opening  of  the  spring  (or  degree  of  curve),  be- 
cause the  nearer  it  approximates  a  straight  line  the  limberer  it  is. 

5.  Upon   the   thickness   of   the   individual    plates,   because   a 
greater  number  of  thin  plates,  making  a  given  thickness,  is  equal 
to  a  smaller  number  of  thick  plates  and  will  be  more  elastic. 

6.  Upon  whether  a  lubricant  is  used  between  the  leaves  or  not. 

Points  on  Spring  Suspension. — As  regards  the  suspension  oi 
springs  of  horse-drawn  vehicles  and  automobiles,  the  careful  ob- 
server will  note  one  point  of  divergence  at  once.  When  elliptic 
or  semi-elliptic,  springs  of  the  ordinary  description  are  used, 
he  will  see  that  in  most  light  horse  carriages  only  two  are  sus- 
pended, one  over  each  of  the  axle  shafts,  across  the  width  of  the 
carriage.  In  automobiles  of  every  build  and  motive  power,  while 
a  single  spring  may  be  thus  attached  to  the  forward  axle,  the 
rear  axle  supports  two,  one  at  each  side  of  the  frame,  and  run- 
ning in  the  length  of  the  carriage.  This  is  a  construction  found 
only  in  the  heavier  patterns  of  horse-drawn  carriages,  and  in  both 
cases  it  is  resorted  to  for  the  purpose  of  neutralizing  the  forward 


SUPPORTS  OF  A  MOTOR  VEHICLE.  g! 

lunge  of  the  body,  inevitable  on  rough  roads  with  a  single  trans- 
verse elliptical  spring.  With  the  horse  carriage  of  the  heavier 
pattern  such  vibration  is  annoying  and  also  hurtful  to  the  body, 
frame  and  springs.  With  the  automobile,  however,  the  case  is 
even  graver ;  for  not  only  will  similar  results  follow  at  high  speed, 
but  the  proper  distance  between  the  motor,  usually  carried  in  the 
body  above  the  springs,  and  the  rear  axle,  will  be  continually  dis- 
turbed, with  consequent  damage  to  sprocket,  chain  and  gears  and 
loss  of  a  steady  drive.  Thus,  in  carriages  which  have  no  other 
provision  against  this  tendency  of  the  rear  axle  to  throw  back- 
ward or  forward  under  the  stress  of  travel,  it  is  necessary  to  use 
a  device  known  as  a  distance  rod  to  maintain  a  fixed  distance  be- 
tween motor  and  drive  axle,  when  the  throw  of  the  springs  would 
otherwise  permit  it  to  be  disturbed.  The  better  method  of  over- 
coming this  danger  is  to  set  the  springs  in  the  length  of  the 
carriage,  as  just  described;  for  thus  most  of  the  violent  jars  in 
this  direction  are  absorbed,  and  the  fixed  relation  of  motor  and 
axle  maintained,  without  rigid  attachments,  which  would  form 
another  notable  occasion  of  accidents.  This  allows  the  springs 
to  lengthen  under  pressure  from  above  or  from  the  direction  of 
travel,  and  further  reinforces  against  sidewise  lunges,  which, 
however,  are  of  far  less  frequent  occurrence. 

Attachments  for  Springs. — The  ends  of  ready  lengthening 
and  extra  elastic  support  are  to  be  accomplished  by  the  use  of 
scroll  elliptics  and  semi-elliptics,  connected  to  the  carriage  body 
by  suitable  links.  Links  are  preferable  in  many  places  on  ac- 
count of  the  ready  action  allowed  in  several  directions,  without 
involving  tendency  to  yield  unduly  under  ordinary  conditions. 
The  high  speed  requirements  of  motor  carriages  makes  it  nearly 
imperative  that  leaf  springs,  either  half  or  full  elliptic,  should  be 
securely  clamped  to  the  supports  by  clips  and  nuts,  rather  than 
by  bolts  through  bolt  holes  in  the  centre.  This  is  true  because 
such  bolt  holes  are  liable  to  prove  a  source  of  weakness  under 
high  speed  conditions  and  to  cause  the  breaking  of  springs  at  the 
very  time  when  their  full  strength  is  most  requisite.  With  clips 


82  SELF-PROPELLED  VEHICLES. 

this  danger  is  wholly  averted,  and,  instead  of  a  weak  point  at  the 
centre,  an  additional  reinforcement  is  obtained. 

The  Alignment  of  Springs. — In  the  act  of  passing  over  an 
obstruction,  such  as  a  large  stone  in  the  roadway,  it  is  evident 
that  the  spring  above  the  axle  of  the  wheel  that  rises  must  be 
compressed  to  an  extraordinary  degree,  unless  it  is  so  rigid  as  to 
lift  the  corner  of  the  vehicle  body  to  a  corresponding  degree.  In 
either  event,  as  is  evident,  there  must  be  some  sidewise  distortion 
of  the  spring,  which,  often  repeated,  must  occasion  its  destruc- 
tion. Because  an  automobile  is  not  usually  built  for  rough  roads, 
few  provisions  have  been  made  against  mishaps  from  this  cause. 
It  is  a  matter,  however,  that  should  interest  the  practical  auto- 
mobilist,  particularly  a  person  about  to  order  a  machine  built  for 
use  in  a  hilly  country,  or  for  long-distance  touring.  In  all  such 
cases  there  should  be  some  means  for  keeping  the  springs  work- 
ing in  a  perfectly  vertical  line. 

Stresses  on  Springs. — The  exact  nature  of  the  stresses  brought 
to  bear  on  the  springs  of  a  motor  carriage  are  shown  diagrammat- 
ically  in  Fig  68.  The  distortion  of  a  full-elliptical  spring,  which 
from  its  structural  elements  allows  greater  action  in  every  direc- 
tion, is  forwards,  when  some  obstacle,  met  by  forward  or  rear 
wheel,  tends  to  throw  the  body  by  its  own  momentum,  and  side- 
wise,  owing  to  the  action  of  forces  precisely  similar  to  those  caus- 
ing side-slipping  of  the  wheels.  The  effect  of  an  obstacle  met  by 
the  wheels  would  be  a  bending-forward  of  the  upper  front  and 
lower  rear  portions  of  the  elliptical  springs,  tending  to  bend  the 
entire  structure  forward  and  downward,  as  shown  in  the  figure. 
This  action  is  intensified  in  the  case  of  the  rear  wheels,  because 
they  bear  the  greater  part  of  the  load. 

The  use  of  semi- elliptical  springs  partly  neutralizes  these  ten- 
dencies, also  reducing  the  danger  of  breakage,  owing  to  the  facts : 

l«  That  a  stiffer  spring  is  required. 

2.  That  a  good  proportion  of  the  stresses  work  downward. 


SUPPORTS  OF  A  MOTOR  VEHICLE. 


83 


A  Three=Spring  Suspension. — A  noteworthy  attempt  to  neu- 
tralize the  tendencies  to  hinges,  forward  and  sidewise,  is  found  in 
the  Hill  spring  suspension  system,  shown  in  Fig.  71.  The  front 
and  rear  springs  are  pivoted  and  linked  to  the  frame  by  one  ex- 
tremity of  each ;  the  opposite  extremities  are  underhung  by  links 
to  a  semi-elliptical  spring — the  "equalizing  spring" — clipped  mid- 
way to  the  side-bar  of  the  body  frame.  The  vehicle  body  is  thus 
supported  at  three  points  on  either  side,  at  the  two  ends  and  in  the 
middle,  with  the  result  that  any  stress  exerted  at  one  of  the  points 
will  be  equalized  by  being  transmitted  to  the  two  others.  It  forms 
in  fact,  a  spring  running  gear.  The  result  is  that  stresses,  which 


PIG.  71 — The  Hill  three-point-suspended  spring  device;   intended   to  compen- 
sate spring  movements  and  to  distribute  stresses. 

would  infallibly  distort  an  ordinary  full-elliptical  spring,  are  dis- 
tributed evenly :  the  equalizing  spring  acting  in  all  such  cases  to 
restrain  any  excessive  movement,  caused  either  by  the  vibrations 
of  travel  or  by  motor  thrust,  and  compelling  the  front  and  rear 
springs  to  lengthen  under  all  stresses. 

Pedestal  Spring  Frames. — Another  noteworthy  device  is  that 
embodied  in  the  Herschmann  steam  truck.  Instead  of  the  usual 
rigid  attachment  by  bolts,  the  spring  has  on  its  lower  face  a 
semi-cylindrical  shoe  that  rests  loosely  upon  a  flattened  portion 
at  the  top  of  the  axle  shaft.  The  axle  works  up  and  down  be- 
tween guides,  four 'in  number,  at  either  side  of  the  vehicle,  and 
formed  of  angle  or  L-shaped  iron  rods.  The  spring  is  bolted 
between  cross-shaped  clip  plates,  the  lower  of  which  carries  the 


84 


SELF-PROPELLED  VEHICLES. 


shoe  above  mentioned,  and  by  this  means  its  movement  is  con- 
fined in  one  vertical  plane.  With  any  elevation  of  one  wheel,  the 
axle  works  against  the  shoe,  merely  lifting  the  spring,  without 
twisting  or  distorting  it  sidewise.  The  Rainier  "pedestal  frame" 
similarly  provides  against  other  than  vertical  movement  of  the 
springs  and  axles  by  two  vertical  guides  extending  downward 
from  the  steel  frame  outside  the  springs.  A  flattened  portion  of 
the  axle-tree  works  up  and  down  between  these  guides. 


PIG.  72.— The  Herschmann  spring  pedestal  device;  showing  springs  resting 
loose  on  the  axle,  their  movements  being  confined  to  the  vertical  by 
guides.  All  throws  of  the  vehicle  body  in  travel  are  overcome  by  this 
arrangement. 

Supplementary  Springs. — A  recently-introduced  device  sub- 
stitutes for  the  shackle  a  coil  compression  spring  arrangement,  so 
mounted  on  a  frame  that  the  upper  member  of  a  scroll-elliptic,  or 
the  spring  hanger  extending  from  the  body  frame,  is  attached 
to  one  end  of  the  coil  spring,  and  the  lower  member  to  the  other. 
The  coil  is  compressed  under  stress  of  travel  absorbing  jars, 
otherwise  transmitted  to  the  body  and  motor. 

A  devise  somewhat  similar  in  effect  has  been  used  on  models 
of  Mercedes  car.  An  elliptical  spring  has  two  small  semi-elliptics 
clipped  and  bolted  inside  the  arcs  of  its  two  members  in  such 
position  as  to  meet  and  engage,  when  extraordinary  stresses  tend 
to  depress  the  main  spring,  thus  absorbing  heavy  jars  and  pre- 
venting excessive  flattening  out.  The  two  smaller  springs  are 
called  the  "check  springs."  One  American  manufacturer  has 


SUPPORTS  OF  A  MOTOR  VEHICLE.  85 

produced  a  similar  device  by  the  use  of  a  large  coiled  spring,  in- 
stead of  the  two  small  laminated  springs  of  the  Mercedes. 

Winton's  twin  compound  spring  is  an  even  better  solution  of 
the  problem  of  varying  loads.  Briefly  described,  it  consists  of 
two  three-leaf  semi-elliptics — the  upper  somewhat  longer  than 
the  under — which  are  joined  by  shackles  at  the  extremities  and 
attached  to  the  spring  supports  of  the  frame.  With  a  light  load, 
under  ordinary  road  conditions,  the  upper  spring  alone  is  in 
action.  When,  however,  the  load  increases  to  a  point  at  which 
it  begins  to  straighten  out,  the  lower  spring  begins  to  receive 
its  share  of  the  load,  thereby  doubling  the  resistance  of  the  sup- 
port. The  effect  of  perfect  compensation  is  thus  obtained,  along 


FIG.  73.— Winton's  twin  compound  spring,  A  and  A,  links  connecting  springs, 
to  supports,  B  and  B;  C,  lower  or  main  spring;  D,  supplementary  spring 
to  take  additional  loads. 

with  a  practical  solution  of  the  serious  problem  of  securing  easy 
riding  with  either  light  or  heavy  load,  a  thing  hitherto  impossible. 
It  may  be  justly  claimed  that  this  device  combines  in  unique 
fashion  the  essential  spring  qualities  of  resistance  and  resilience. 

Absorbing  Vibrations. — While,  as  we  have  seen,  a  flexible 
spring  is  required  for  the  purpose  of  deadening  the  numerous  an- 
noying and  harmful  shocks  encountered  in  operating  a  car  over  an 
uneven  roadway,  excessive  flexibility  is  liable  to  intensify  such 
movements.  A  spring  serves  its  function  in  bending  downward, 
or  straightening,  under  the  stress  of  a  moving  load,  but  it  shows 
itself  unequal  to  the  task  assigned  it,  when,  by  continued  vibra- 
tions, it  merely  breaks  up  or  distributes  the  shock  in  a  series  of 
bounds  and  jolts,  destructive  alike  to  body,  machinery  and  tires, 
and  from  which  there  is  no  relief  or  protection. 


86 


SELF-PROPELLED  VEHICLES. 


It  is  obvious  that  some  device  for  ensuring  the  gradual  return 
of  the  spring  to  its  normal  shape,  deadening  its  rebounds  and 
after-movements  by  absorbing  them  with  some  form  of  friction 
resistance,  is  highly  desirable.  Similar  results  are  achieved  in 
other  branches  of  mechanic  arts  by  the  use  of  "dash-pots,"  etc. 
Applied  to  neutralize  the  rebound,  or  after-movements  of  a  motor 
spring,  the  result  is  greater  comfort  for  passengers,  smaller  injury 
to  machinery  and  nearly  double  durability  of  pneumatic  tires. 


FIG.  74. — The    Truffault    Spring    Suspension   for   neutralizing   shocks   due   to 
sudden  spring  action. 

One  of  the  best-known  of  such  devices  is  the  Truf- 
fault suspension  shown  in  Fig.  74.  It  first  attained  distinction 
through  its  adoption  on  Peugeot  cars,  and  has  since  done  excellent 
service. 

Briefly  described,  it  consists  of  the  two  arms,  A  and  B,  joined 
frictionally  by  bolt  C.  The  arm,  A,  carries  a  cup-like  bronze  shell, 
D,  and  the  arm,  B,  a  plate,  F.  A  cup-like  piece  of  oil-soaked  raw- 
hide is  secured  between  the  plate  and  the  shell,  being  screwed  by 
the  nut  G,  on  the  bolt,  C.  An  oil-soaked  leather  washer  separates 
it  from  the  plate,  F.  This  nut  is  split  and  is  locked  in  place  by  the 
collar,  H.  By  screwing  sufficiently,  the  nut,  G,  any  desired  degree 
of  friction  may  be  obtained.  The  arms,  A  and  B,  are  joined  to  the 
frame  and  the  axle  by  two  cone-like  frictional  joints,  which  also 


SUPPORTS  OF  A  MOTOR  VEHICLE.  87 

can  be  regulated.  All  these  movable  frictional  parts  offer  a  con- 
stant resistance  to  the  vibration  of  the  spring  both  ways,  and  it  is 
easy  to  see  that  when  the  wheel  strikes  an  obstruction  the  arms 
come  together ;  but  instead  of  flying  back  as  does  the  free  spring, 
it  is  retarded  by  the  friction  and  moves  gradually  to  its  normal  po- 
sition, since  the  friction  is  always  the  same,  while  the  tension  of 
the  spring  diminishes  as  it  approaches  its  normal  position. 


FIG.  75.— The  De  Dion  &  Bouton  Spring  Compensating  Steering  Device. 

Radius  Rods. — A  spring  support  involves  the  use  of  some 
device  for  maintaining  a  fixed  distance  between  the  motor  and  the 
driven  axle.  This  generally  takes  the  form  of  a  radius  rod  at- 
tached to  a  bearing  at  either  end,  so  as  to  describe  an  arc,  with 
the  rear  axle  as  a  centre,  while  the  springs  rise  or  fall  in  travel. 
A  turnbuckle  permits  the  length  of  the  rod  to  be  varied  ac- 
cording to  requirements.  With  the  two-chain  drive  to  the  rear 
wheels,  loose  on  a  dead  axle,  two  distance  rods,  one  at  each  end, 
are  usually  provided.  With  a  single-chain  drive  to  a  live  axle 
one  rod  usually  suffices.  With  bevel-gear  drive  a  slip  joint  on  the 
propeller  shaft  usually  suffices  to  maintain  a  fixed  distance,  al- 
though, as  must  be  evident,  an  extra  strain  is  thereby  thrown  upon 
the  bevel  casing,  which  is  only  too  liable  to  break,  with  the  other 
forms  of  violence  it  must  endure. 


88  SELF-PROPELLED   VEHICLES. 

Compensations  for  the  Steering  Gear. — Some  automobiles 
include  spring  compensating  devices  for  the  steering  gear, 
although  with  modern  forms  of  hand-wheel  a  link  swung 
between  ball  joints  is  amply  sufficient.  On  the  lighter  forms 
of  De  Dion  carriage  a  somewhat  complicated  although  highly 
efficient  compensation  was  used.  As  shown  in  an  accompany- 
ing figure,  a  V-shaped  piece  A,  constructed  of  two  pieces,  is 
attached  to  the  tubular  front  cross-piece  of  the  body  frame  at  D, 
and  pivoted  on  the  ball  joint  at  F,  to  the  lower  V-shaped  piece,  B. 
This  is  also  pivoted  at  F,  and  is  attached  to  the  axle-tree  at  E. 
The  T-piece,  C,  is  also  pivoted  at  E  rigidly  with  B,  so  as  to  turn 
sideways  with  it.  It  carries  the  links  C'  and  C",  which  actuate 
the  steering  arms  of  the  two  stud  axles.  The  link,  H,  is  at- 


FIG.  76. — Spring  Compensating  Steering  Device  used  on  the  Oldsmobile  Car- 
riage. 

tached  to  the  arm,  G,  and  when  moved  forward  or  back  by  the 
worm  gear  and  pinion  arrangement  at  the  base  of  the  steering- 
wheel  pillar,  moves  the  entire  structure,  A,  B  and  C,  on  the 
pivots,  D  and  E,  to  the  right  or  left,  as  desired.  The  object  of  the 
device  is  to  allow  of  a  certain  up  and  down  movement,  as  the 
springs  yield,  without  disarranging  the  steering  gear  or  vibrating 
the  steer  wheel.  In  such  cases  the  V-pieces,  A  and  B,  move  on 
the  ball  joint  F,  thus  permitting  the  points,  D  and  E,  to  be  ap- 
proached and  separated,  as  the  springs  move. 

In  the  Oldsmobile,  built  with  longitudinal  side  springs  be- 
tween the  axles,  the  steering  pillar  is  attached  to  the  front  axle 
through  a  small  elliptic  spring,  which,  bearing  against  the  bot- 
tom of  the  body,  is  compressed  or  distended,  as  it  falls  or  rises, 
thus  enabling  the  steering  to  be  positive  and  uninterrupted  under 
all  conditions. 


CHAPTER   EIGHT. 

MOTOR   CARRIAGE   WHEELS. 

Requirements  in  Motor  Carriage  Wheels. — Motor  carriage 
wheels  must  have  five  qualities  of  construction : 

I.  They  must  be  sufficiently  strong  for  the  load  they  are  to 
carry,  and  for  the  kind  of  roads  on  which  they  are  to  run. 

2.  They  must  be  elastic,  or  so  constructed  that  the  several 
parts — hub,  spokes  and  felloes,  or  rim — are  susceptible  of  a  cer- 
tain flexibility  in  their  fixed  relations,  thus  neutralizing  much 
vibration,  and  allowing  the  vehicle  greater  freedom  of  move- 
ment, particularly  on  short  curves  and  when  encountering 
obstacles. 

3.  They  must,  furthermore,  be  sufficiently  light  to  avoid  ab- 
sorbing unnecessary  power  in  moving. 

4.  They  must  be  able  to  resist  the  torsion  of  the  motor,  which 
always  tends  to  produce  a  tangential  strain.     This  is  the  reason 
why  tangent  suspended  wire  wheels  are  invariably  used  in  auto- 
mobiles, instead  of  the  other  variety,  having  radially-arranged 
spokes. 

5.  They  must  have  sufficient  adhesion  to  drive  ahead  without 
unduly  absorbing  power  in  overcoming  the  tendency  to  slip  on 
an  imperfectly  resistant  road-bed. 

The  importance  of  the  two  last  considerations  may  be  readily 
understood,  in  view  of  the  fact  that  the  wheels  of  motor  car- 
riages receive  the  driving  power  direct,  instead  of  being  merely 
rotating  supports,  like  the  wheels  of  vehicles  propelled  by  an 
outside  tractive  force. 

Wooden,  Steel  and  Wire  Wheels. — Motor  carriage  wheels, 
at  the  present  time,  are  either  wooden,  of  the  so-called  "artillery'' 


90  SELF-PROPELLED   VEHICLES. 

type,  or  of  steel  tubing.  A  few  years  ago  suspended  wire  wheels, 
of  the  bicycle  variety,  were  extensively  applied  to  motor  car- 
riages of  all  powers,  and  their  claims  to  superiority  were  vigor- 
ously discussed.  They  are  now  so  seldom  seen  that,  we  may 
unhesitatingly  say,  they  have  been  abandoned. 

Suspended  Wire  Wheels. — Like  steel  tubular  framework, 
also  nearly  obsolete,  the  alleged  advantages  of  wire  wheels  were 
given  as  combined  lightness  and  strength.  A  suspended  wire 
wheel,  weight  for  weight,  can  undoubtedly  carry  a  heavier  load 
than  a  wooden  wheel,  without  danger,  but  it  cannot  sustain  as 
great  stress  sidewise,  or  at  right  angles  to  its  plane,  which  is  the 
line  of  a  wheel's  greatest  weakness,  and,  in  automobile  work,  of 
the  greatest  stress  acting  upon  it. 

A  wire  wheel  driven  against  a  curb  with  sufficient  force  will 
have  its  rim  dented,  with  the  result  of  loosening  all  its  spokes  and 
ruining  it.  A  wooden  wheel,  on  the  other  hand,  may  have  a  gap 
in  it  and  still  be  serviceable.  It  may  even  run  with  one  or  several 
spokes  broken  off.  A  wire  wheel  being  suspended  on  its  spokes — 
the  load  being  hung  between  the  hub  and  the  perimeter — is  bound 
to  suffer  in  proportion  to  the  number  of  points  of  suspension  lost. 
A  wooden  wheel,  being  supported  at  both  hub  and  perimeter  by 
its  spokes,  has  a  certain  power  of  compensating  or  distributing 
the  strain,  so  that,  while  a  deficiency  of  support  at  any  one  point 
is  of  no  advantage,  it  does  not  always  involve  destruction. 

Steel  Tubular  Wheels. — Steel  tubular  wheels,  which  have 
been  used  to  a  certain  extent  on  automobiles,  have  the  advantage 
of  possessing  such  strength,  particularly  in  a  sidewise  direction, 
as  tubular  construction  possesses,  and  are  immensely  superior  to 
wire  wheels.  Among  the  advantages  claimed  are  : 

1 .  Superior  strength  to  either  wire  or  wood. 

2.  True,  balanced  running,  as  a  pulley  on  a  shaft. 

3*.  Practical  immunity    from   dishing  or  crushing  with  the 
hardest  use,  or  in  ordinarv  accidents. 
4.  Immunity  to  rust. 


MOTOR  CARRIAGE  WHEELS. 


91 


5.  Ability  to  stand  the  twist  and  tension  of  severe  strains  in 
the  transmission  of  power. 

6.  Rims  formed  from  a  continuous  tube. 

7.  Perfect  alignment  of  all  parts. 

Steel  wheels  are  imperfectly  elastic,  however,  and  have  very 
little  of  the  desirable  spring  effect.  Thus,  while  such  a  wheel,  if 
well  made,  will  endure,  without  rupture,  strains  far  in  excess  of 
those  encountered  under  service  conditions,  such  distortion  would 
result  as  would  unfit  it  for  extended  use. 


Fio.  77—  A  typical  W-oden  Artillery  or  Wedge  Wheel,  bhowins?  manner  of  setting 
the  spokes,  and  the  construction  of  the  hub. 

Tests  conducted,  some  years  since,  on  one  make  of  steel  car- 
riage wheel  demonstrated  ability  to  resist  a  dead  weight  at  the 
axle  up  to  3,200  pounds,  a  sidewise  pressure  of  1,600  pounds, 
and  a  combined  pressure  at  rim  and  axle  up  to  3,500  pounds. 
Beyond  these  points,  however,  permanent  bending  and  distortion 
resulted. 

Wooden  Artillery  Wheels. — Wooden  wheels  are  almost  uni- 
versally used  for  automobiles  at  the  present  time.  The  type  in 


92  SELF-PROPELLED  VEHICLES. 

vogue  is  the  so-called  "artillery"  wheel,  constructed  with  wedge 
spokes  set  together  around  the  nave,  and  a  hub  formed  of  steel 
plates  at  front  and  rear,  bolted  through  the  spokes  and  holding 
the  axle  box  in  place.  This  is  substantially  the  model  originated 
by  Walter  Hancock,  an  early  steam  carriage  builder,  and  is  by 
far  the  most  solid  design  of  wooden  wheel  possible.  It  is,  in 
fact,  practically  of  one  piece,  having  strength  to  withstand  side- 
wise  strains  that  would  speedily  wreck  a  wheel  of  the  type  used 
in  horse  carriages. 

Dishing  of  Wheels. — Where  wooden  wheels  are  used  in  any 
kind  of  vehicle,  the  effect  of  elasticity  is  greatly  increased  by 
"dishing";  that  is,  by  inclining  the  spokes  from  the  exterior 
plane  of  the  rim  to  the  centre  point  of  the  axle  spindle,  so  as  to 
make  the  wheel  a  kind  of  flattened  cone.  This  construction  has 
the  effect  of  transforming  the  spokes  into  so  many  springs,  pos- 
sessing elastic  properties,  and  renders  the  wheel  capable  of  being 
deformed  under  sidewise  stress.  The  shocks  of  collision  with 
obstacles  are  thus  distributed  through  the  flexibly  connected 
parts,  as  could  not  be  the  case  if  the  wheel  were  made  in  one 
piece  or  on  one  plane,  and  the  consequent  wear  and  strain  is 
greatly  reduced.  The  dish  of  the  wheels  is  usually  balanced  by 
slightly  inclining  the  axle  spindle  from  its  centre  line,  thus  bring- 
ing the  lowest  spoke  to  a  nearly  vertical  position  with  relation 
to  the  ground.  A  great  resisting  power  to  shocks  produced  by 
obstacles  such  as  is  afforded  by  dished  wheels  is  of  far  less  im- 
portance in  vehicles  designed  for  good  roads  as  are  most  auto- 
mobiles, which  need  only  such  inclination  of  the  spokes  as  will 
provide  for  the  even  distribution  of  shocks  and  the  maintenance 
of  uniformity  in  pressure. 

Advantages  Attained  by  Dishing. — The  significance  of  the 
word  "dish"  is  obvious,  when  we  consider  that  it  indicates  a  dia- 
metrical section  of  about  the  shape  of  a  saucer  or  shallow  dish. 
While,  as  we  have  seen,  this  shape  furnishes  a  very  desirable 
spring  effect  against  sidewise  strains  and  shocks,  such  as  are 
met  in  swinging  around  a  corner  or  sliding  against  a  curb — since, 
although  a  wheel  is  always  weakest  sidewise,  it  is  difficult  to 


MOTOR  CARRIAGE  WHEELS 


93 


thrust  a  cone  inside  out — there  are  several  considerations  that 
render  it  a  desirable  feature  for  wagons  of  all  descriptions. 

i.  The  first  of  these  has  reference  to  maintaining  a  balanced 
hang  to  the  wheel.  Under  the  conditions  of  travel  a  wheel 
acquires  the  tendency  to  crowd  on  or  off  the  spindle,  with  the 
result  that  it  eventually  wears  loose,  as  may  be  frequently  found, 
particularly  on  heavy  carts.  Since  the  spindle  is  tapered  it  is 
necessary  that  its  outer  centre  should  be  lower  than  the  inner, 
and  then  in  order  to  counteract  the  outward  inclination  of  the 
wheel,  and  consequent  tendency  to  roll  outwardly,  the  spindle 
end  must  be  also  carried  forward  sufficiently  to  make  the  wheel 


FIQ  78.— Type  of  Wooden  Artillery  Wheel  constructed  with  tongue-and-groove 
joints  between  the  spoke  wedges,  ensuring  greater  strength  and  rigidity. 

"gather,"  which  is  to  say,  follow  the  track.  A  moderate  dish 
contributes  to  the  end  of  bringing  the  tire  square  to  the  ground, 
while  at  the  same  time  enabling  the  wheel  to  rotate  without 
undue  wear  at  the  axle. 

2.  Another  constructional  advantage  involved  in  the  dishing 
of  wooden  wheels  relates  to  the  method  of  shrinking  on  the  iron 
tire.  As  is  known,  the  tire  is  first  forged  to  as  nearly  the  re- 
quired diameter  as  possible,  after  which  it  is  heated,  so  as  to 


94  SELF-PROPELLED  VEHICLES. 

cause  it  to  enlarge  its  diameter,  and  in  this  state  placed  about  the 
rim  of  the  wheel.  When  once  more  cooled  it  fits  tightly.  As 
frequently  happens,  however,  a  tire  is  made  somewhat  too  small 
for  a  wheel,  which  involves  that,  in  the  act  of  shrinking,  it  will 
cither  force  the  wheel  into  a  polygonal  shape  or  crush  one  or 
more  of  the  spokes.  By  giving  the  wheel  a  dish,  the  shrinkage  of 
the  tires  merely  increases  the  inclination  of  the  cone  from  base 
to  apex,  the  spring  of  the  spokes  being  quite  immaterial,  all 
suffering  to  about  the  same  extent. 

Dished  Wheels  for  Automobiles. — Ever  since  the  motor  car- 
riage industry  achieved  anything  like  large  proportions,  the 
possibility  of  using  dished  wheels  has  been  actively  discussed. 
The  numerous  advantages  to  be  attained  have  tempted  several 
inventors  to  devise  some  suitable  means  for  using  them  at  least 
on  heavy  wagons.  Among  these  may  be  mentioned  the  De  Dion 
jointed  axle  and  the  Daimler  driving  differential.  However,  since 
a  large  part  of  the  real  efficiency  of  a  dished  wheel  lies  in  an 
inclination  of  its  axle,  it  is  easy  to  see  that  its  application  to  an 
automobile  presents  serious  constructional  problems.  With  a 
divided  rear  axle  shaft  of  the  usual  description,  it  would  be 
impracticable  to  incline  the  axles  from  the  differential,  except 
by  some  form  of  universal  or  slip- joint,  as  in  the  De  Dion 
carriages.  Consequently,  until  the  patents  on  this  device  expire, 
the  differential  gear  cannot  be  attached  above  the  springs,  as  is 
desirable,  for  many  reasons,  nor  can  dished  wheels  be  used. 

The  Use  of  Wood  Wheels. — Charles  E.  Duryea  enumerates 
the  following  advantages  to  be  found  in  using  wooden  wheels : 

1.  The  construction,  proportions  and  strength   suitable  for 
given  requirements  have  been  carefully  determined  by  years  of 
practical  experience. 

2.  Being  practically   one   piece,   they   do   not   deteriorate   by 
usage  in  bad  weather  and  are  readily  cleaned. 


MOTOR  CARRIAGE  WHEELS.  95 

3.  If  broken,  they  may  be  anywhere  repaired,  all  the  parts  being 
easily  obtainable. 

4.  They  will  often  give  good  service  even  in  a  bady  damaged 
condition. 

5.  Experience  has  shown  that  they  are  far  more  elastic  than 
wire  wheels. 

6.  In  wire  wheels  any  attempt  to  make  the  hub  of  proper  length 
to  give  spread  to  the  spokes  under  strain  results  in  a  clumsy 
appearance. 

7.  If  the  spokes  are  proportionately  strengthened   the  wire 
wheel  becomes  heavier  than  the  wood  wheel. 

8.  The  greater  number  of  spokes  in  a  wire  wheel,  and  their 
proximity  at  the  hub,  where  dirt  and  moisture  are  collected, 
prevents  easy  cleaning  and  promotes  rust. 

In  regard  to  elasticity  Mr.  Duryea  says : 

"As  a  matter  of  fact,  the  wood  wheel  is  far  more  elastic  than  the  steel 
wheel,  as  may  be  readily  seen  by  watching  a  light  buggy  drive  over  car 
tracks  or  rough  payments.  The  rims  of  the  wheels  vibrate  sideways,  some- 
times as  much  as  two  inches,  without  damage  to  the  wheel  or  axle,  on 
which  account  fewer  broken  axles  will  be  had  when  wood  wheels  are 
used  instead  of  wire  ones.  While  it  is  true  that  the  pneumatic  tire  prac- 
tically removes  the  necessity  of  an  elastic  wheel,  there  is  no  need  of  refus- 
ing to  accept  a  valuable  feature." 

Dimensions  of  Automobile  Wheels. — As  a  general  propo- 
sition we  may  assert  that  the  larger  the  wheel  the  smaller  the 
shocks  experienced  in  passing  over  inequalities  in  the  road-bed, 
and  the  smaller  the  buffing  qualities  required  in  the  tires.  Thus 
it  is  that  a  wheel  five  feet  in  diameter  will  sink  only  one-half  inch 
in  a  rut  one  foot  wide,  while  a  thirty-inch  wheel  will  sink  nearly 
three  times  as  deep,  with  the  result  that  the  resiliency  of  its  tires 
must  be  enormously  larger,  in  order  to  compensate  the  greater 
shock  experienced.  The  larger  wheel  also  rises  less  quickly  over 
obstructions.  These  are  considerations  of  great  importance  in 
motor  vehicles,  in  which  any  device  for  the  reduction  of  vibration 


96 


SELF-PROPELLED    VEHICLES. 


and  concussion  is  desirable.  Furthermore,  when  a  wheel  is 
properly  tired,  the  road  resistance  to  its  steady  and  even  rotation 
is  decreased  as  the  square  of  the  increase  in  its  diameter,  such  a 
wheel  of  sixty  inches  diameter  decreasing  the  resistance  in  a 
ratio  of  between  50  per  cent,  and  70  per  cent.,  as  compared  with  a 
wheel  of  thirty  inches  diameter. 


PIG.  79.— Diagram  showing  the  relative  drop  into  a  road  rut  between  a  small  carriage 
wheel  and  one  twice  its  diameter. 

There  are,  however,  other  methods  for  neutralizing  the  shocks 
on  rough  roads.  The  end  of  obtaining  a  low  and  easy-running 
rig  may  be  achieved  quite  as  well  by  increasing  the  width  of  the 
vehicle,  the  length  of  the  springs  and  the  size  of  the  tires,  as  by 
adding  to  the  height  above  the  ground.  Also,  the  broad  tire  is 
superior  to  the  nai  row  one  in  the  very  same  particular  that  it  will 
not  sink  so  quickly  into  mud  and  sand,  and,  by  its  greater  buffing 
properties,  neutralizes  the  concussion  otherwise  experienced  with 
small  wheels.  These  and  other  similar  considerations  have 
largely  determined  the  prevalent  practice  of  using  wheels  of 
moderate  diameter  for  automobiles. 


MOTOR  CARRIAGE  WHEELS.  97 

On  the  other  hand,  as  many  claim,  the  small  wheel  is  destruc- 
tive to  tires  in  inverse  ratio  to  its  diameter  and  an  increase  in 
proportion  would  involve  a  corresponding  economy  in  rubber. 
In  this  point,  as  in  others,  experiment  is  a  better  guide  than 
theory,  and  if,  as  some  claim,  heavy  high-speed  vehicles  can  be 
constructed  with  wheels  of  large  diameter,  they  have  only  to  build 
their  vehicle  and  try  it  out. 

Arguing  that  it  is  a  distinct  advantage  to  enlarge  the  diameter 
of  motor  carriage  wheels  for  the  purposes  of  obtaining  an  offset 
to  the  concussions  experienced  on  rough  roads,  to  obtain  higher 
speed  within  certain  limits,  and  to  secure  greater  durability  for 
the  tires,  particularly  when  solid  rubber  tires  are  used,  a  promi- 
nent American  tire-maker  writes  as  follows : 

"To  prevent  traveling  on  the  rim  a  tire  should  bind  the  whole  surface 
of  the  rim.  The  higher  the  wheel  the  more  adhesive  surface  there  is 
for  the  tire.  When  the  tire  is  bound  in  by  lugs  the  natural  kneading 
and  straining  of  it  between  the  lugs  will  in  time  either  shear  off  the  lugs 
or  loosen  them.  Another  reason  why  a  large  wheel  is  to  be  preferred  from 
a  tire-maker's  point  of  view  is  that  a  large  wheel  does  not  turn  round 
so  many  times  in  a  given  distance,  and  consequently  does  not  wear  the 
tire  so  fast.  If  a  tire  travels  very  fast  under  a  heavy  load  the  kneading 
of  it  causes  heating  and  cracking,  which  are  intensified  on  the  small  wheel. 
Our  experience  has  proved  that  a  large  wheel  greatly  reduces  the  above 
difficultes." 

Troubles  with  Large  Wheels. — As  against  theoretical  ad- 
vantages involved  in  the  use  of  large  wheels,  there  are  numerous 
objections  of  equal,  if  not  greater,  importance.  Among  these 
may  be  mentioned  the  fact  that,  the  larger  the  wheel  the  greater 
must  be  its  proportional  strength  and  weight  of  construction,  in 
order  to  neutralize  the  ill  effects  of  torsional  motor  effort,  and 
disproportionate  road  resistance.  Indeed,  a  moment's  reflection 
will  show  that  a  wheel  of  sixty-inch  diameter,  built  on  the  same 
dimensions  of  hub,  spokes  and  felloes,  as  a  wheel  of  thirty-inch 
diameter,  will  possess  considerably  more  than  twice  the  liability  to 
strain  and  breakage  from  the  causes  above  named.  If  we  may 
assert  that  such  increased  liability,  as  compared  with  the  increase 
of  diameter  is  on  a  ratio  of  three  to  two,  it  is  obvious  that  a  wheel 


98  SELF-PROPELLED   VEHICLES. 

of  sixty-inch  diameter  must  be  very  nearly  three  times  as  heavily 
and  strongly  built  as  a  wheel  of  thirty-inch  diameter,  in  order  to 
insure  its  durability.  We  may  readily  judge,  then,  at  about  what 
point  of  increased  diameter  a  light  pleasure  carriage  would  be 
equipped  with  cart  wheels.  This  is  only  one  of  the  numerous 
difficulties  involved  in  attempting  to  use  large  wheels  with  a 
modern  high-speed  motor. 


CHAPTER    NINE. 

SOLID  RUBBER  TIRES  J  THEIR  THEORY  AND  CONSTRUCTION. 

The  Question  of  Tires. — All  automobiles  and  cycles,  and  a 
large  number  of  horse-drawn  vehicles,  use  rubber  tires.  The 
object  is  twofold: 

1.  To  secure  a  desirable  spring  effect. 

2.  To  obtain  the  requisite  adhesion  to  the  road. 

While,  with  properly  constructed  springs,  the  first  result  may 
be  achieved  with  steel  tires,  the  second  is  almost  impracticable 
when  the  power  is  applied  direct  to  the  wheel.  Thus,  if  a  light 
automobile  be  equipped  with  steel  tires,  the  wheels  will  not  drive 
on  an  imperfectly  resistant  road-bed,  unless  most  of  the  load  be 
placed  over  the  rear  axle,  which,  when  it  is  too  great  in  propor- 
tion, involves  the  disadvantage  that  the  steering  will  be  unre- 
liable, the  forward  wheels  tending  to  skid,  instead  of  turning  the 
vehicle  in  a  positive  manner.  It  is  not  always  practicable  to 
remedy  this  difficulty,  either  by  strewing  sand  in  front  of  the 
wheels  or  by  applying  power  to  all  of  them.  An  attempt  to  pro- 
duce adhesion  by  constructing  tires  with  teeth  or  corrugations,  or 
by  giving  them  extra  breadth,  would  increase  the  weight  for  only 
temporary  advantage.  The  simplest  and  readiest  resort  is  found 
in  the  use  of  rubber  tires. 

The  Reduction  of  Vibration. — On  the  point  of  reduced  vibra- 
tion in  a  vehicle,  as  it  is  related  to  the  kind  of  tires  used,  W. 
Worby  Beaumont  says : 

"It  must  also  be  remembered  that  the  greater  comfort  of  the  rider  is  due 
to  lessened  severity  of  vibration  and  shock,  and  this  is  a  relief  in  which 
everything  above  the  tires  participates.  Now,  this  means  a  reduction  in  the 
wear  and  tear  of  every  part  of  the  car  and  motor  which  can  easily  be  under- 
estimated. The  experience  of  the  London  cab-owners,  whose  records  of 
every  cost  are  carefully  kept,  is  a  proof  of  this ;  and  they  find  that  rubber- 
tired  wheels  suffer  very  much  less  than  the  iron-tired;  every  part  that 

99 


100  SELF-PROPELLED   VEHICLES. 

could  be  loosened  or  broken  by  constant  severe  weather  or  hard  vibration 
remains  tight  very  much  longer;  the  breakage  of  lamp  brackets,  hangers 
and  other  parts  does  not  occur,  and  that  even  the  varnish,  which  being 
hard  and  breakable,  lasts  a  great  deal  longer.  The  same  immunity  of  the 
high-speed  car  is  obtained  by  pneumatics,  as  compared  with  solids,  and  its 
value  is  greater  in  proportion  to  the  greater  value  of  the  vehicle." 

The  Working  Unit. — The  situation  to  be  met  in  providing 
proper  supports  for  a  motor  carriage  may  be  more  readily  under- 
stood by  considering  the  vehicle  and  the  roadway  as  the  two  com- 
ponents of  a  working  unit,  precisely  like  two  mutually-moving 
parts  of  any  machine.  In  both  cases  these  parts  must  be  cal- 
culated and  arranged  to  move,  the  one  upon  the  other,  with  the 
least  possible  friction  and  wear.  An  English  authority  on  motor 
vans  writes  as  follows : 

"The  prime  fact  with  which  engineers  have  to  deal  is  that  the  success  or 
failure  of  any  design  mainly  depends  on  the  nature  of  the  road  on  which 
the  van  is  to  be  worked.  The  V-slides  of  a  planing  machine  are  integral 
parts  of  the  whole.  The  permanent  way  of  a  railroad  and  the  rolling  stock 
constitute  together  one  complete  machine.  In  just  the  same  way  the  King's 
highway  must  be  regarded  as  an  integral  part  of  all  and  every  combination 
of  mechanical  appliances  by  which  transport  is  affected  on  the  road.  In 
one  word,  if  we  attempt  to  dissever  the  road  from  the  van,  we  shall  fail  to 
accomplish  anything.  Two  or  three  years  ago,  the  maker  of  a  steam  van 
told  us  that  he  was  surprised  to  find  how  little  power  was  required  to 
work  his  van.  He  had  been  running  it  on  wood-paved  streets.  A  week  or 
two  later  on  he  was  very  much  more  surprised  to  find  that  on  fairly  good 
macadam  after  rain  he  could  do  next  to  nothing  with  the  same  van.  In 
preparing  the  designs  for  any  van,  the  quality  of  the  roads  must  not  for 
a  moment  be  forgotten;  and  it  will  not  do  to  estimate  the  character  of  the 
road  by  anything  but  its  worst  bits.  A  length  of  a  few  yards  of  soft,  sandy 
bottom  on  an  otherwise  good  road  will  certainly  bring  a  van  which  may 
have  being  doing  well  to  grief.  Curiously  enough  we  have  found  this 
apparently  obvious  circumstance  constantly  overlooked.  This  is  not  all, 
however.  A  road  may  be  level,  hard,  and  of  little  resistance  to  traction, 
and  yet  be  very  destructive  to  mechanism.  This  type  of  road  is  rough  and 
"knobby;"  it  will  shake  a  vehicle  to  pieces,  and  the  mischief  done  by  such 
road  augments  in  a  most  painfully  rapid  ratio  with  the  pace  of  the  vehicle. 
Jarring  and  tremor  are  as  effectual  as  direct  violence  in  injuring  an  auto. 
Scores  of  examples  of  this  might  be  cited.  One  will  suffice.  In  a  motor 
van  a  long  horizontal  rod  was  used  to  couple  the  steering  gear  to  the 


SOLID  RUBBER  TIRES. 


101 


leading  wheels.  The  rod  was  broken  solely  by  vibration.  It  was  replaced 
by  a  much  heavier  and  stronger  bar.  That  was  broken  in  much  the  same 
way,  and  finally  guides  had  to  be  fitted  to  steady  the  rod  and  prevent  it 
shaking." 

Analogies  for  a  Buffing  Support. — In  automobile  building 
the  principal  concern  is  for  the  vehicle,  which  must  be  con- 
structed so  as  to  endure  the  most  unfavorable  conditions  of  road- 


Fio.  80.— Wheel  of  the  -'Lif u"  Steam  Truck,  showing  a  solid  rubber  cushion  tire 
secured  in  position  and  protected  by  metal  shoes  around  the  rim.  Although  the 
attachment  is  so  rigid  as  to  prevent  creeping,  a  very  effective  spring  effect  is 
obtained  by_  combination  of  the  cushion  tire  and  shoes.  It  is  effective  for  heavy 
service,  which  would  soon  destroy  an  ordinary  tire. 

bed.  The  effect  on  the  road  is  quite  secondary.  In  the  construc- 
tion of  railroad  locomotives,  on  the  other  hand,  both  components 
of  the  working  unit,  the  vehicle  and  the  tramway,  must  be  con- 
sidered :  both  must  be  constructed  to  interact  with  a  minimal 
wear  and  damage.  In  this  connection  we  may  quote  Matthias 
N.  Forney,  a  well-known  locomotive  authority.  In  speaking  of 
springs,  which  in  locomotives  perform  some  of  the  functions 
delegated  to  flexible  tires  in  automobiles,  he  says ; 


102  SELF-PROPELLED  VEHICLES. 

"A  light  blow  with  a  hammer  on  a  pane  of  glass  is  sufficient  to  shatter 
it.  If,  however,  on  a  pane  of  glass  is  laid  some  elastic  substance,  such 
as  india-rubber,  and  we  strike  on  that,  the  force  of  the  blow  or  the  weight 
of  the  hammer  must  be  considerably  increased  before  producing  the  above 
named  effect.  If  the  locomotive  boiler  is  put  in  place  of  the  hammer,  the 
springs  in  place  of  the  india-rubber,  and  the  rails  in  place  of  the  glass, 
the  comparison  will  agree  with  the  case  above." 

While  in  automobiles  the  effect  on  the  road-bed  is  incon- 
siderable, the  light  and  delicately-geared  machinery  must  be 
protected  from  damage — the  anvil  must  be  shod.  Whence  it 
follows  that,  in  the  absence  of  anything  like  the  steel  rail  surface 
of  a  railroad,  utility  of  tires  increases  directly  with  their  yielding 
and  shape  restoring  properties.  The  more  readily  these  functions 
are  exercised,  the  smaller  the  wear  on  all  the  elements  composing 
the  working  unit.  Furthermore,  the  necessity  in  this  particular 
becomes  greater  in  proportion  to  the  weight  and  contemplated 
speed  capacity  of  the  vehicle,  and,  beyond  the  point  where  pneu- 
matic tires  are  practical,  must  be  compensated  by  more  efficient 
springs  and  lower  rates  of  travel. 

Rubber  Tires  for  Automobiles. — There  are  two  varieties  of 
rubber  tire  in  use  for  every  kind  of  vehicle  except  cycles:  the 
solid  tire  and  the  pneumatic,  or  inflatable  tire.  As  is  generally 
known,  the  pneumatic  tire  was  first  devised  in  order  to  furnish 
the  needed  resiliency  in  bicycles,  and  for  the  same  purpose  it  has 
been  found  useful  in  automobiles.  It  is  also  superior  in  point 
of  tractive  qualites,  "taking  hold"  of  the  road-bed  far  more 
effectively  than  the  best  solid.  It  has,  however,  one  notable 
disadvantage,  the  constant  liability  to  puncture,  with  the  con- 
sequent danger  of  being  rendered  useless.  In  order  to  remedy 
this  defect,  inventors  and  manufacturers  have  introduced  such 
features  as  thickening  the  tread  of  the  tire,  increasing  its  re- 
sistance to  puncture  by  inserting  layers  of  tough  fabric  in  the 
rubber  walls,  and  reinforcing  the  tread  surface  in  various  ways. 

At  the  present  time  pneumatic  tires  are  almost  universally  used 
On  automobiles,  solids  being  found  only  on  electric  vehicles,  in- 


SOLID  RUBBER  TIRES. 


103 


tended  for  use  on  city  streets,  or  on  heavy  slow-speed  trucks  and 
vans.  It  is  not  too  much  to  say,  however,  that  the  finality  has 
not  yet  been  reached,  and  that  there  are  still  reputable  authorities 
who  hold  that,  with  perfected  spring  attachments,  the  solid  tire 
may  yet  see  a  wider  sphere  of  usefulness. 


Fig.  81. 


Fig.  83. 

FIGS.  81,  82  and  a3.— Three  varieties  of  Solid  Rubber  Tire,  showing  shape  and  methods 
of  attaching  on  the  rims.  Fig.  81  shows  a  broad  tire,  which  is  attached  by  forcing 
over  the  edges  of  the  channel-shaped  rim,  to  which  it  is  vulcanized,  and  alsj 
secured  by  endless  wires,  welded,  as  shown.  Fig.  82  shows  a  tire  secured  by  bolta 
through  the  base,  also  by  annular  lugs  on  the  rim  sides  fitting  into  channels.  Fig. 
83  shows  an  attachment  made  by  connecting  at  the  base  by  a  peripheral  T-piece, 
also  by  bolts  securing  sides  of  channel-shappd  rim.  All  three  varieties  show  rim 
channels,  so  shaped  as  to  allow  of  considerable  distortion,  laterly,  under  load. 

W.  Worby  Beaumont  writes  : 

"For  high-speed  running  with  comfort  over  street  crossings  and  level 
railway  crossings,  the  expensive  pneumatic  is  necessary,  but  it  is  a  high 
price  to  pay  for  this  luxury,  and  it  will  only  be  paid  by  the  few  who  will 
pay  anything  for  speed.  After  a  while,  when  automobile  travel  settles 
down  to  the  moderate  speeds  of  the  majority,  and  to  the  requirements  of 
business,  the  better  forms  of  solid  or  nearly  solid  tire,  in  which  a  cqnv 


104  SELF-PROPELLED  VEHICLES. 

paratively  small  amount  of  internal  movement  of  the  rubber  takes  place, 
will  probably  be  most  used.  A  hard  pneumatic  tire  is  superior  to  this  for 
ease  at  the  bad  places  in  roads  and  over  crossings,  but  greater  strength 
of  material  suitable  for  the  purpose  than  is  yet  available  is  required  to  meet 
all  the  conditions." 

As  to  the  durability  of  solid  tires,  under  constant  use,  he  says : 

"With  regard  to  solid  tires,  the  experience  of  the  London  hansom  cabs 
is  of  much  interest.  A  pair  of  i%  or  1^4  inch  tires  will  last  from  a  little 
over  six  months  to,  at  most,  nine  months.  The  most  rapid  wear  is  on  those 
cabs  which  have  the  best  and  fastest  horses,  if  we  except  those  cabs  that 
have  constantly  to  run  in  districts  where  the  road  surfaces  are  destroyed 
by  the  prevalence  of  tramways.  *****  if  thirty  miles  per  day  for 
the  hansom  driven  by  men  who  are,  as  most  are,  allowed  two  horses  per 
day,  and  assuming  300  days  per  year,  then  a  year's  mileage  would  be  9,000. 
They  run,  however,  not  more  than  eight  months  at  best  before  tire  renewal, 
so  that  the  mileage  is  not  probably  more  than  about  5,500  to  6,000.  *  *  * 
The  mileage  of  the  tires  on  the  four-wheel  c<ibs  is  much  greater,  as  would 
be  expected,  from  the  smaller  weight  each  wheel  carries  and  the  lower 
speed.  The  miles  traveled  per  month  will  also  be  less.:< 


Structural  Requirements  in  Solid  Tires. —  The  shape  and 
methods  of  attaching  solid  tires  to  the  wheel  rims  must  both  be 
determined  with  reference  to  the  source  and  pull  of  the  strains 
likely  to  affect  them.  The  weight  of  the  vehicle  is  nearly  the 
greatest  source  of  wear,  but  even  this  consideration  is  closely 
rivaled  by  the  torsional  strain  from  the  engine  and  in  braking, 
particularly  in  viev\  of  the  almost  universal  use  of  comparatively 
small  wheels.  Indeed,  no  part  of  the  wheel  could  suffer  greater 
strain  than  the  tire  from  the  condition  last  mentioned.  In  view  of 
the  properties  of  rubber,  it  may  be  readily  seen  that  increasing  the 
thickness  of  the  solid  tire,  in  proportion  to  the  increased  weight 
of  the  vehicle,  will  largely  neutralize  the  destructive  effects  due  to 
every  cause  involved  in  the  structure  of  the  running  gear  and 
its  load.  By  this  means  is  obtained  a  greater  width  of  tread,  with 
a  probably  smaller  total  abrasion  of  the  surface  from  contact  with 
the  road-bed,  and  a  greater  opportunity  for  distributing  and  neu- 
tralizing the  harmful  strains. 


SOLID  RUBBER  TIRES. 


105 


The  tendency  in  solid  tires  is  that  cuts,  due  to  stones  or  other 
sharp  obstacles,  tend  to  spread  to  the  centre  of  the  tire  across  the 
tread.  This  is  due  to  the  quality  of  the  strains  transmitted  from 
the  wheels,  as  above  noted,  and  in  ordqr  to  prevent  this  tendency 
from  destroying  the  tire  it  is  necessary  to  vary  the  shape.  Ac- 
cordingly, tires  are  made  with  bevel  edges,  rather  than  on  square 
lines,  and  the  profile  is  slightly  rounded.  This  conformation, 
together  with  good  width  at  the  rim,  is  able  to  provide  for  absorb- 
ing much  of  the  surplus  vibration,  while  decreasing  the  ill  effects 
due  to  the  combined  action  of  a  heavy  load  and  road  resistance. 


Fig  84. 


Fig.  85. 


FIGS.  84  and  85.— Two  Models  of  the  Swinehart  Solid  Clincher  Tire,  which  derives  a 
good  degree  of  resiliency  from  its  construction  with  beaded  tread  and  concaved 
sides. 

On  the  whole  it  greatly  prolongs  the  life  of  the  tire.  The  curved 
surface  at  the  tread  and  the  bevel  edges,  tending  to  flatten  under 
the  load,  provide  a  sufficient  width  to  ensure  good  adhesion  and 
the  other  advantages  belonging  to  a  wide  tire,  while,  at  the  same 
time,  reducing  to  the  minimum  the  tendency  to  spread  tears  and 
cuts,  as  above  mentioned. 

The  Present  Situation  on  Solid  Tires. — In  justice  to  the 
earnest  efforts  of  numerous  inventors  to  improve  the  types  and 
efficiency  of  solid  tires,  it  must  be  confessed  that  the  situation 
has  changed  materially  in  the  last  few  years.  As  shown  in  Figs. 
81,  82  and  83  the  prevailing  types  of  tire  to  a  very  recent  date 
had  a  section  of  approximate  rounded  triangular  shape,  which, 
firmly  secured  at  the  sides,  all  around  the  rim,  possessed  a  min- 


106  SELF-PROPELLED  VEHICLES. 

imum  degree  of  distortability  and  elasticity.  That  such  tires  were 
"unresilient"  and  liable  to  tear  is  hardly  remarkable.  Further- 
more, that  they  were  subject  to  serious  cutting  by  stones  and 
other  sharp  objects  seems  no  less  than  inevitable.  Recent  im- 
proved tires,  departing  entirely  from  such  models,  have  attained 
a  good  degree  of  resiliency  and  of  immunity  from  such  accidents 
by  devices  like  perforating  and  concaving  the  sides  of  the  tire  all 
around  above  the  rim. 

The  Swinehart  solid  clincher,  shown  in  Figs.  84  and  85,  em- 
bodies the  excellent  features  of 

1.  A  Heavily  Beaded  Tread. 

2.  Deeply  Concaved  Sides. 

3.  Superior  Elasticity  in  the  Rubber. 

The  beaded  tread  and  concaved  sides  permit  of  considerable 
compression  under  load  and  the  ability  of  absorbing  heavy  jolts 
without  serious  vibration.  As  will  be  readily  understood,  the 
construction  seems  to  go  far  to  warranting  these  claims.  The 
manufacturers  confidently  assert  that  their  tires  are  equal  to  any 
kind  of  service  up  to  35  miles  per  hour,  but  claim  high  efficiency 
at  speeds  above  40  miles  under  a  heavy  touring  car. 


CHAPTER  TEN. 

THE  CONSTRUCTION   AND   TYPES  OF   PNEUMATIC  TIRES. 

Advantages  of  Pneumatic  Tires. — The  most  valuable  quality 
of  the  pneumatic  tire  is  its  resiliency,  or  the  ability  to  bounce  in 
the  act  of  regaining  its  normal  shape  after  encountering  an  ob- 
stacle in  the  road.  On  encountering  a  stone,  for  example,  it  will 
yield  to  a  certain  extent,  absorbing  or  "swallowing  it  up,"  at 
the  same  time  exerting  a  pressure  sufficient  to  restore  its  normal 
shape.  This  quality  begets  two  advantages  for  easy  driving: 

1.  It  does  away  with  much  of  the  lifting  up  of  the  wheel  in 
passing  over  obstacles,  which  is  otherwise  inevitable. 

2.  It  enables  the  tire  to  obtain  a  better  grip  on  the  road-bed. 

Commensurate  advantages  are  also  derived  from  this  cushion- 
ing quality  in  colliding  with  obstacles  to  one  side  or  other 
of  the  tread,  whence  the  total  pressure  exerted  through  the 
spokes  is  greatly  reduced  and  such  obstructions  exert  only  a 
fraction  of  their  usual  power  to  retard  the  easy  and  steady  opera- 
tion of  the  motor  and  steering  gear.  In  both  cases,  also,  a  large 
part  of  the  shocks  and  vibrations,  usually  transmitted  direct  to  the 
springs,  are  completely  absorbed.  No  solid  tires  could  furnish 
anything  like  such  advantages  in  operation ;  the  usual  result,  even 
with  the  most  flexible  springs,  being  that  the  motor  is  much 
shaken  or  damaged,  or  its  action  largely  impaired.  This  is  par- 
ticularly true  of  the  use  of  solid  tires  on  electric  vehicles,  the 
damage  resulting,  both  in  point  of  efficiency  and  durability,  hav- 
ing been  estimated  by  several  authorities  as  high  as  30  per  cent. 

Pneumatic  Tires,  Speed  and  Power. — A  prominent  tire  ex- 
pert furnishes  the  following  data  on  pneumatic  tires,  based  on 
experiments : 

107 


108  SELF-PROPELLED  VEHICLES. 

"I  have  made  tests  with  2^/2  and  3  inch  solid  rubber  tires  on  automobiles 
ranging  from  16  to  24  horse-power,  and  on  carriages  weighing  i  ton  to 
ll/2  tons,  and  have  ascertained  that  both  of  these  automobiles  could  run 
safely  on  a  good  road  at  a  maximum  speed  of  42  kilometers,  25  i-io  miles, 
an  hour.  When  the  driver  attempted  to  go  beyond  this  speed  (always 
on  a  perfect  road)  the  motor  was  subjected  to  such  fearful  vibrations  its 
complete  demolition  was  threatened.  Under  the,  same  conditions  of  horse- 
power, weights  and  tires,  but  on  what  is  considered  a  bad  road,  it  was 
impossible  to  attain  more  than  15  miles  an  hour.  The  same  autos,  with 
pneumatic  tires,  made  60  and  70  miles  an  hour  on  an  average  road." 

While  the  average  automobilist  never  contemplates  such  high 
speeds  as  60  or  70  miles  per  hour,  it  is  only  fair  to  remark  that 
speed,  combined  with  general  road  qualities,  furnishes  the  test, 
conditions  for  the  jar-absorbing,  vibration-neutralizing,  and  ad- 
hesion-increasing properties  of  pneumatic  tires.  Furthermore, 
as  the  result  of  numerous  experiments,  it  may  be  correct  tc 
assert  that  a  tire,  best  fitted  to  endure  test  conditions  as  to  speed., 
is  also  within  certain  limits  the  most  suitable  type  and  make  to 
travel  under  heavy  loads,  with  a  minimum  of  traction  effort.  For, 
as  most  figures  seem  to  indicate,  the  decrease  of  traction  effort 
is  in  ratio  with  the  elasticity  of  the  vehicle's  support. 

It  must  not  be  forgotten  that  such  tests  as  these  were  made 
exclusively  with  high-speed  cars,  which,  as  is  generally  admitted 
even  at  the  present  day,  cannot  operate  satisfactorily  without 
pneumatics;  again,  that  the  tires  used  were  of  the  ordinary 
round  or  conical  tread  pattern  which  permit  of  very  little  dis- 
tortion under  load  and  very  slight  resiliency. 

Within  recent  years  several  types  of  solid  and  semi-solid  or 
cushion  tires  have  been  introduced,  which  seem  to  furnish  suf- 
ficient resiliency  and  traction  efficiency  for  ordinary  service. 
Among  these  the  most  noteworthy  is  the  Swinehart  tire.  As 
shown  in  the  figure  page  105,  its  features  are  a  corrugated  tread 
and  concaved  sides.  The  makers  claim  for  their  tires  superiority 
over  pneumatics  on  any  except  the  heaviest  high-speed  cars,  not 
only  in  point  of  traction  and  speeding,  but  also  in  hill-climbing. 

Single  and  Double=Tube  Tires. — There  are  two  varieties  of 


PNEUMATIC  TIRES.  109 

pneumatic  tire,  the  single  and  the  double  tube.  The  double-tube 
tire  was  first  introduced,  and  in  all  its  various  forms  consists  of 
an  inner,  or  air  tube,  made  of  thin  and  elastic  india-rubber,  en- 
closed in  the  outer  or  case  tube,  built  up  of  strong  fabric  and  a 
tougher  and  denser  kind  of  rubber.  The  case  tube  is  split  on  its 
inner  face,  which  bears  against  the  periphery  of  the  wheel,  in 
order  to  allow  the  air  tube  to  be  readily  removed  at  any  time  for 
repair  or  replacement.  The  single-tube  tire  was  devised  as  an 
improvement,  whereby  the  layers  of  thread  and  tough  rubber 
are  formed  upon  and  around  the  delicate  air  tube,  making  the 
two  tubes  really  one.  The  double-tube  tire  is  most  commonly 
used  on  automobiles,  being  preferred  on  account  of  several  ad- 
vantages which  will  be  presently  mentioned. 

Fabric  Tires. — Pneumatic  tires  of  both  varieties  were  formerly 
built  up  with  layers  of  some  tough  woven  fabric,  such  as  canvas, 
in  which  the  warp  and  filler  are  of  the  same  size,  as  in  ordinary 
duck  and  other  cloth.  This  kind  of  fabric,  known  as  "square 
woven,"  has  many  objectionable  features,  particularly  when  the 
manufacturing  process  is  not  most  carefully  conducted.  Unless 
the  most  improved  methods  are  employed,  the  rubber,  during 
vulcanization  under  heat,  develops  wrinkles  in  the  canvas  fabric, 
which  causes  unequal  strains  on  the  various  plies,  or  layers,  and 
constitutes  the  defect  known  as  "buckling."  Even  without  this 
defect,  a  woven  fabric  tire  is  liable  to  develop  internal  chafing 
between  the  contiguous  threads  of  each  layer,  which  results  in 
heating,  to  the  eventual  deterioration  of  the  entire  structure. 

Thread  Tires. — Experience  has  proven  that  strength  and  im- 
munity from  heating  demand : 

1.  That  there  shall  be  sufficient  clearance  between  the  con- 
tiguous threads  of  a  tire  fabric  to  allow  a  large  and  firm  attach- 
ment between  the  rubber  layers  above  and  below  each  ply. 

2.  That   the  possibility   of  direct  contact  between   individual 
threads  shall  be  prevented,  thus  removing  the  occasion  for  chafing 
and  heating. 


110 


SELF-PROPELLED   VEHICLES. 


In  order  to  accomplish  these  results,  the  so-called  thread  fabric 
is  used  for  both  varieties  of  tire. 

SingIe=Tube  Thread  Tires. — The  methods  of  manufacturing 
single-tube  thread  tires  is  thus  explained  by  Pardon  W.  Tilling- 
hast,  their  original  inventor: 

"A  fabric  must  be  employed  in  which  there  is  no  starting  point  of  sep- 
aration between  the  fabric  and  rubber,  and  one  that  does  not  have  a  sub- 
stantially smooth  surface,  or  a  surface  that  is  continuous  in  the  same  plane. 
The  attaching  surface  of  the  fabric  presented  for  union  with  the  rubber 
must  be  greatly  in  excess  of  that  furnished  by  the  fabrics  in  use  at  the 
present  time.  A  plurality  of  plies  may  be  used,  some  of  the  plies  having 


Fig.  86. 


Pig.  87. 


FIGS.  83  and  87.— The  construction  of  two  types  of  Tillinarhast  Single-Tube  Tires,  Fig. 
86,  shows  the  formation  of  the  fabric  into  a  succession  of  loops.  Fig.  87  shows  the 
open  thread  fabric  tire  in  which  separate  threads  are  wound,  in  the  manner  indi- 
cated, over  each  successive  rubber  layer  or  tube. 

a  more  open  weave  or  construction  than  other  plies,  and  all  plies  separated 
by  rubber,  which  will  give  in  effect  a  single  tube  or  mass  of  rubber,  having 
fibrous  threads  extending  throughout  the  mass  to  prevent  bursting,  and 
binding  the  whole  structure  into  a  substantially  indestructible  body. 

"Another  means  of  accomplishing  the  same  end  consists  essentially  of 
employing  a  fabric  which,  when  built  into  a  tire,  will  have  the  same  effect 
that  a  bath  towel  would  if  it  was  inclosed  and  imbedded  in  the  rubber, 
with  the  threads  sufficiently  strong  to  withstand  the  inclosed  an  pressure, 


PNEUMATIC  TIRES. 


Ill 


the  little  loops  or  fibres  extending  away  from  the  general  plane  of  the 
main  fabric  into  the  surrounding  rubber  and  being  vulcanized  therein,  fur- 
nishing an  increased  surface  for  union  with  the  rubber;  the  general  sur- 
face line  of  the  fabric  in  each  construction  is  to  be  broken  so  that  it  is  not 
continuous  in  the  same  plane,  and  there  is  no  starting  point  of  separation 
between  the  fabric  and  rubber." 

Accompanying  figures  illustrate  the  construction  of  two  re- 
cent types  of  tire.  One  of  them  is  built  up  with  a  number  of 
strands  of  thread  running  longitudinally  on  the  tube  and  wound 
spirally  with  other  threads  which  hold  them  securely  under  in- 
flation. The  spiral  windings  are  then  pushed  along  the  length 
of  the  tube,  so  as  to  reduce  the  distance  between  the  windings 


FIQ.  88.—  Diagram  of  the  successive  thread  layers  in  the  case-tube  of  a  double-tubo 

thread  tire. 

from  one-quarter  inch  to  less  than  one-eighth  inch,  with  the  result 
that  the  intermediate  sections  of  the  longitudinal  threads  are 
pushed  up  into  series  of  loops,  thus  forming  stronger  attachments 
for  the  fabric,  when  held  in  the  material  of  the  rubber  wall  built 
up  over  this  layer  of  threads.  Tillinghast's  other  method  of 
strengthening  the  fabric  against  any  cause  tending  to  burst  or 
tear  the  walls,  involves  several  layers  of  plies  or  layers  of  threads 
wound  on  in  two  diagonal  directions,  each  one  being  in  a  more 
open  construction  than  the  last,  the  closest  being  on  the  inmost  ply. 


112  SELF-PROPELLED   VEHICLES. 

Manufacture  of  Thread  Tires. — In  the  construction  of  thread 
fabric  double-tube  tires,  each  case  tube  is  built  up  of  plies  of 
strong  threads  running  parallel,  and  unwoven,  except  for  light 
cross  threads  at  intervals  to  hold  the  main  threads  in  position. 
Each  ply  is  vulcanized,  above  and  below,  to  rubber  layers,  which 
are  applied  by  heat,  under  pressure,  causing  the  rubber  to  be 
forced  between  the  threads,  like  plaster  between  the  lathes  of  a 
wall,  and  entirely  surrounding  them.  The  entire  body  of  the  case 


Fig.  89.  Fig.  90. 

FlOS.  89  and  90.— Sections  of  double  and  single-tube  pneumatic  tires,  showing  shapes 
of  rirns  and  methods  of  fastening. 

tube  is  thus  in  practically  one  piece,  made  extra  strong  and  re- 
sistant by  arranging  the  -threads  of  each  separate  ply  at  right 
angles  with  those  of  the  one  above  or  below  it.  Each  thread 
being  thus  thoroughly  imbedded  in  rubber,  those  in  consecutive 
layers  cannot  come  into  contact.  There  is  consequently  no  abra- 
sion or  heating,  and  the  threads  act,  both  separately  and  together, 
to  strengthen  the  structure  in  every  direction  of  stress.  The  end 
of  strength  is  achieved  by  using  several  plies  of  thread,  all  in- 
serted under  even  tension,  which  cannot  be  done  with  square- 
woven  fabric.  A  further  advantage  claimed  by  the  advocates  of 
thread  fabric  is  that  the  rubber  more  readily  and  more  com- 
pletely penetrates  the  interstices  between  the  threads  than  is 
possible  with  the  square  weave. 


PNEUMATIC    TIRES.  113 

Attachments  for  Tires. — Where  single-tube  tires  are  used  on 
automobile  wheels  the  attachment  is  made  by  bolts  passing 
through  the  rim  and  secured  by  wing  nuts  on  the  inside  surface, 
or  by  cementing  the  tire  to  the  rim. 

Each  bolt  is  of  one  piece  with'  a  head  or  plate  imbedded  in 
the  fabric.  While  such  attachment  is  sufficiently  strong  under 
ordinary  conditions,  particularly  when  the  tire  is  thoroughly  in- 
flated, it  is  desirable  to  spread  hard  cement  in  the  rim  channel, 
in  order  to  prevent  the  accumulation  of  dust  and  sand,  which  are 
always  seriously  destructive  to  the  tire. 

Single-tube  tires,  attached  as  described,  are  very  well  suited 
for  light  vehicles  and  low  speeds,  but  not  at  all  for  heavy,  high- 
speed service.  The  principal  reason  is  that  the  attachment,  al- 
though probably  the  best  possible  under  the  necessary  conditions 
of  service,  does  not  altogether  neutralize  the  tendency  of  the 
single  tube  to  creep,  nor  prevent  rolling  off  the  rim,  should  the 
lugs  become  loosened  or  broken.  Apart  from  the  dangers  of 
puncture,  rim-cutting,  etc.,  shared  by  both  varieties  of  tire,  the 
single  tube,  as  at  present  designed,  exhibits  the  tendency  to  creep 
to  such  an  extent  that  the  greatest  strain  is  always  brought  to 
bear  upon  the  lugs.  Being  of  rounded  contour,  it  is  also  liable 
to  roll  on  any  attempt  to  make  a  sharp  corner  at  high  speeds,  the 
attachments  at  the  base  often  proving  insufficient  to  resist  the 
sidewise  stress,  and  being  repeatedly  loosened.  Thus,  although 
embodying  the  great  advantage  of  being  more  easily  treated  for 
puncture,  the  single-tube  is  practically  inferior  to  the  double-tube 
tire. 

Comparison  of  Tires. — As  regards  the  relative  merits  of  the 
two  varieties  of  pneumatic  tire,  we  may  profitably  quote  Charles 
E.  Duryea.  He  states  his  conclusions  as  follows : 

"The  ordinary  round  tire  lying  in  an  arc-shaped  rim,  as  is  the  common 
method,  cannot  utilize  its  side  walls  properly  when  meeting  an  obstacle, 
since  it  is  flattened  toward  the  rim  and  caused  to  bend  at  the  side  abruptly 
at  two  places ;  being  bent  outward  over  the  edge  of  the  rim  and  inward  at 
its  widest  point.  The  outward  bend,  together  with  dirt  which  may  get 
between  tire  and  rim,  tends  to  chafe  the  tire  on  the  edge  of  the  rim,  a 
phenomenon  commonly  known  as  rim  cutting.  The  other  bend  cannot 


134 


SELF-PROPELLED   VEHICLES. 


stretch  the  outer  layers  of  fabric,  so  it  must  compress  the  inner  fabric  and 
inner  rubber,  which  compression  rapidly  causes  a  crack,  weakening  the 
tire  from  the  inside,  with  the  result  that  in  a  short  while  the  tire  begins 
to  swell  along  the  sides  and  finally  bursts.  Any  rim,  therefore,  which 
will  hold  the  tire  at  the  bottom  only,  and  yet  preserve  it  from  rolling 
sidewise  on  the  rim,  is  conducive  to  long  life  of  tire,  for  it  leaves  the  side 
walls  free  from  short  bends  and  increases  the  depth  of  the  tire,  which 
increases  its  beneficial  results  as  well." 


<_ 2/2 


FIG.  91.— Diagram  illustrating  the  relative  degree  of  flattening  consequent  on  deflat- 
ing a  double-tube  pneumatic,  mechanically  secured  to  base,  and  a  cemented 
single-tube  pneumatic,  through  one-half  diameter  above  edges  of  rim.  .Note  the 
sharp  corners  of  the  single  tube. 

An  accompanying  figure  of  a  mechanically  fastened  double- 
tube  tire  and  of  a  single-tube  cemented  tire  with  arc-shaped 
rim,  shows  their  shapes  when  inflated  and  when  deflated  to 
one-half  their  diameter;  demonstrating  that  since  a  double-tube 
tire  may  be  compressed  further  than  a  single  tube,  a  small  tire 
of  the  former  variety  is  as  efficient  in  smoothing  the  road  as  a 
larger  one  of  the  latter  variety.  A  proportionate  deflation  of  the 
two  shows  a  further  advantage,  in  that  the  walls  of  a  double-tube 
tire  are  bent  much  less  for  a  given  compression  than  those  of  a 
single  tube,  and  are  forced  against  the  edges  of  the  rim  with  much 
less  compression.  The  single-tube  tire  does  not  flatten  out  so 
widely  in  proportion  to  its  diameter  as  does  the  double  tube, 
which  fact  is  of  importance,  because  added  width  means  added 
supporting  surface,  tending  to  resist  further  compression  as  it 
increases. 


PNEUMATIC  TIRES.  115 

Duryea  concludes,  therefore,  that : 

"The  best  automobile  tire  is  the  one  mechanically  fastened  so  as  to 
relieve  the  fabric  from  the  strain  of  holding  the  tire  in  position.  Its 
fabric  must  be  as  strong  as  possible,  because  of  the  heavy  service  which 
means  a  long  fibre  closely-woven  canvas  of  the  greatest  possible  strength 
and  the  fewest  necessary  thicknesses  which  arrangement  is  less  liable  to 
puncture  or  tear  than  any  thread  fabric  and  is  yet  as  flexible  as  the  neces- 
sary strength  will  permit.  Being  mechanically  fastened,  the  fabric  need 
not  be  stretched  in  the  direction  of  the  length  of  the  tire  which  increases 
the  resilience  and  lessens  the  strain  and  liability  of  rupture  in  passing  over 
obstructions." 

As  may  be  readily  understood,  a  further  advantage  gained  by 
using  a  double-tube  tire,  mechanically  fastened  at  the  base,  is  that 
the  sidewise  strains  encountered  in  turning  corners,  are  not  so 
liable  to  cause  rolling  off  the  rim.  In  bicycles  this  danger  is 
largely  averted  by  the  rake,  or  inclination,  taken  by  the  wheels 
in  turning  corners,  which  maintains  the  entire  wheel-structure, 
including  the  tire,  in  one  plane.  But  in  automobiles  this  rake 
cannot  be  obtained  except  with  the  front  or  steer  wheels,  the 
result  being  that  the  strain  brought  upon  a  tire  in  turning  cor- 
ners at  high  speed  is  enormous.  A  tire  standing  high  above  the 
rim  and  rigidly  attached  at  the  base  is  capable  of  a  very  con- 
siderable sidewise  deformation  without  particularly  great  dan- 
ger of  rupture  or  other  accident.  Howbeit,  if  the  inflation  be 
insufficient,  such  side  strains  are  very  liable  to  loosen  the  fasten- 
ings, particularly  when  clamps  are  used. 

Advantages  of  Double  Tubes. — Double-tube  tires  are  prac- 
tically immune  from  creeping,  on  account  of  the  security  of  their 
attachment  to  the  wheel  rim.  They  will  not  roll  off,  like  single 
tubes,  although  the  attempt  to  turn  sharp  corners  at  high  speed 
strains  the  fabric  excessively,  and  at  times  may  result  in  rupture. 
There  are  two  general  methods  of  attachment :  by  clinches  and  by 
side-flange.  In  both  there  is  a  secure  joint  between  the  tire  base 
and  the  rim  at  every  point  around  the  periphery  of  the  wheel. 


116 


SELF-PROPELLED   VEHICLES. 


Clincher  Tires. — A  very  large  proportion  of  double-tube  tires 
are  of  the  clincher  type,  being  constructed  with  rubber  and  fabric 
flanges  on  either  side  of  the  case  tube,  which  fit  snugly  into 
channels  formed  by  inturning  the  edges  of  the  rim.  These  chan- 


Fig.  92. 


Fig.  93. 


Fig.  94. 


Fig.  95. 


FiGS.  92, 93, 94  and  95.— Four  Forms  of  Double-Tube  Pneumatic  Tire,  showing  methods 
of  securing  to  the  rims.  Fig.  92,  the  Goodyear  Detachable  Side-Flange  Tire,  with 
reversible  side-rings;  Fig.  93,  the  Goodyeur  Clincher  with  side-rings  reversed; 
Fig.  94,  the  Dunlop  Tire,  showing  tubular  side-rings ;  Fig.  95,  the  Fisk  Tire,  SLOW- 
ing  bottom  flanges  and  retaining  rings  held  to  rim  by  clips  and  nuts. 


nels  are  the  clinches.  In  removing  the  case  tube  it  is  necessary  to 
insert  a  flat  tool  between  it  and  the  rim  and  pry  them  apart. 
This  operation  is  tedious  and  also  involves  very  great  strain  on 
the  fabric.  A  careless  hand  may  also  cut  or  bruise  the  air  tube, 
particularly  when  it  is  not  protected  by  a  flap. 


PNEUMATIC  TIRES.  117 

Side-Flange  Tires. — The  side-flange  tire  is  gradually  sup- 
planting the  clincher  in  very  many  quarters,  embodying,  as  it 
does,  the  advantage  of  being  readily  removable,  without  strain  or 
injury  to  the  fabric  or  rubber.  The  original  patterns  of  this 
variety  of  tire  were  held  upon  the  flat  rim  between  two  annular 
plates  or  flanges,  bolted  through  the  felloe.  The  Goodyear  tire, 
probably  the  first  of  its  type,  was  further  enforced  by  strands  of 
braided  wire  at  the  base  on  either  side  of  the  opening  of  the  case 
tube.  Its  later  forms  have  the  wires,  but  are  retained  on  the  rim 
by  two  endless  steel  flange  rings  and  an  open  steel  locking  ring, 
which  holds  the  flanges  in  position. 

The  Dunlop  Tire. — The  latest  Dunlop  tire  is  logically  in  the 
side-flange  class.  Its  special  feature  has  always  been  two  end- 
less wire  rings  at  either  side  of  the  base,  which  furnishes  a  suf- 
ficiently firm  attachment  to  the  rim.  Former  models  of  this  tire 
were  removable  in  the  same  manner  as  clinchers,  by  prying  over 
the  side  of  the  rim  channel.  At  present,  however,  removal  is 
accomplished  by  loosening  one  of  the  tubular  retaining  rings, 
which  is  cut  and  securely  held  in  place  by  screwing  up  a  turn- 
buckle. 

The  Fisk  tire  has  its  case  tube  flanged  at  the  base  in  some- 
what the  same  fashion  as  a  clincher,  but  is  secured  to  the  flat 
rim  by  two  metal  rings  fitting  snugly  over  the  flanges  and  held 
tightly  in  place  by  lugs  and  bolts. 


lib 


SELF-PROPELLED  VEHICLE. 


> 


CHAPTER  ELEVEN. 

PNEUMATIC  TIRE  TROUBLES. 

Accidents  to  Pneumatic  Tires. — The  serviceability  of  pneu- 
matic tires  depends  upon  a  number  of  considerations,  quite  apart 
from  afly  question  of  their  merits  as  manufactured  products. 
That  a  tire  should  embody  the  best  available  materials  and  work- 
mansh;.p  must  be  evident  on  reflection,  and  any  occasions  for  dis- 
ablement arising  from  faults  in  these  particulars  need  no  lengthy 
consideration.  If  the  case  tube  is  poorly  made,  it  will  heat  and 
crack.  If  the  wall  is  too  thin  it  will  tear  or  cut.  If  the  walls  and 
tread  are  too  thick  and  heavy  the  difficulty  of  bending  under 
load  is  increased,  sharp  corners  being  formed  and  the  fabric 
ruptured.  If  the  attachment  to  the  rim  is  insufficient  the  tire 
will  creep. 

Causes  of  Excessive  Wear  in  Tires. — A  tire  may  be  injured 
in  a  number  of  ways,  on  account  of  faulty  attachments,  careless- 
ness or  hard  service.  Among  the  commonest  forms  of  wear  and 
fear  are : 

1.  Creeping. 

2.  Puncture. 

3.  Rim-cutting. 

4.  Cracking  of  the  walls. 

5.  Excessive  wear  on  the  walls  or  tread. 

6.  Chemical  action. 

The  Creeping  of  Tires. — Creeping  is  found  almost  exclusively 
in  single-tube  tires.  ft  is  due  to  the  fact  that  the  weight  of  the 
vehicle,  in  process  of  travel,  tends  to  centralize  the  pressure  on 
the  rubber  walls,  and  cause  the  tire  to  bulge  just  forward  of  the 
point  of  contact  with  the  ground.  As  may  be  readily  recognized, 
a  continued  succession  of  such  bulgings  tends  both  to  loosen  the 
adhesion  of  the  tire  and  the  rim,  and  also  to  cause  the  tire  to 

119 


SELF-PROPELLED  VEHICLES. 

push  forward  from  the  ground,  and  thus  around  the  rim,  in  the 
effort  to  relieve  and  distribute  the  pressure.  As  a  result,  when 
inflation  is  insufficient,  great  strain  and  pull  will  be  exerted  where 
the  valve  is  joined  to  the  tire,  and  a  rupture  often  follows  at  that 
point.  Even  were  it  possible  to  obviate  the  last-named  accident, 
it  is  evident  that  the  service  of  a  tire,  thus  loosened  by  the  creep- 
ing process  is  impaired.  Moreover,  it  would  inevitably  roll  side- 
ways from  the  rim  before  it  had  been  long  in  use.  Also,  if  loose, 
it  chafes  at  the  rim  and  wears  quickly.  The  only  assurance  against 


FIG.  100.— Leather-reinforced  Pneumatic  Tire,  showing  outside  case  of  leather  and 
spiked  leather  head. 

creeping  in  a  single-tube  tire  is  found  in  reliable  bolt  and  lug 
fastenings.  Double-tube  tires  are  immune  from  creeping  on  ac- 
count of  having  complete  peripheral  attachments  in  clinches,  side 
flanges,  etc. 

Puncture  of  Tires. — The  accident  known  as  puncture  is  such 
a  piercing  of  the  air  tube  as  allows  the  air  to  escape  and  flatten 
the  tire.  It  is  generally  caused  by  a  sharp  stone  or  a  nail  piercing 
the  tread,  in  which  event  the  air  tube  must  be  immediately  re- 
paired or  else  a  new  one  substituted. 

Among  other  possible  causes  of  puncture  are: 

1.  Nipping  of  the  air  tube  by  the  tire  refaoving  lever ;  by  the 
lug  of  the  screw  bolt;  by  the  edge  of  the  case  tube. 

2.  Sand  or  other  hard  substances  in  the  case  tube. 
Puncture  is  always  an  annoying  accident,  but  with  the  later 

makes  of  tire,  particularly  those  equipped  with  a  leather  tread,  it 
happens  less  often  than  formerly. 


PNEUMATIC  TIRE  TROUBLES.  121 

Rim-Cutting. — Rim-cutting  of  pneumatic  tires  is  a  mishap 
arising  generally  from : 

1.  Sand  or  sharp  particles  lodged  between  the  tire  and  the 
edges  of  the  rim,  which,  particularly  when  the  tire  is  partially 
deflated,  cut  through  the  outer  layer  of  rubber  to  the   fabric 
beneath. 

2.  Overloading,  or  compelling  a  tire  to  carry  a  weight  greater 
than  its  dimensions  warrant.     This  causes  the  tire  to  flatten,  in 
spite  of  persistent  extra  inflating,  and  the  result  is  nearly  always 
shearing-off  at  the  edges  near  the  points  where  the  flanges  en- 
gage the  clinches. 

3.  Defective  or  bent  rims.     Rims  may  be  unsuitable  for  given 
makes  of  tire,  because  made  for  some  other  style.     It  is  essential 
that  the  tire  fit  the  rims  perfectly,  since,  if  the  attachment  is  not 
tight,   movement  and   chafing  result,   or   stones  and   sand   find 
lodgment;  if  it  is  too  tight  the  pressure  against  the  edges  of  the 
rim  is  excessive. 

Loose  or  ill-fitting  studs  always  allow  some  movement  of  the 
tire,  and  occasion  cutting,  at  least  in  spots  around  the  rim. 

These  mishaps  occur  less  frequently  at  present  than  those  due 
to  bent  or  rusty  rims,  which  work  the  same  havoc  as  those  that 
fit  poorly.  It  is  particularly  necessary  to  keep  the  rim  in  per- 
fect repair,  to  clean  out  all  evidences  of  rust,  and  to  remedy  any 
bends  or  breaks  at  once. 

4.  Insufficient  inflation  is  often  a   cause  of  cutting,  even  when 
the  rims  are  in  perfect  repair.     It  is  necessary  to  keep  the  tires 
pumped  hard  at  all  times.    If  cutting  then  results,  it  is  the  least 
possible  evidence  that  the  tires  are  too  small  for  the  load  they 
are  obliged  to  carry. 

Carriage  builders  of  the  present  day  are  able  to  calculate  very 
accurately  the  endurance  of  a  tire  under  a  predetermined  load. 
But  if  the  vehicle  is  used  for  purposes  not  contemplated  in  the 
original  design,  it  is  evident  that  the  tires  will  not  endure.  Exces- 
sive speeds,  like  overloading,  will  work  destruction  of  the  best 
tires  Indeed,  both  extremes  amount  to  the  same  thing  in  the  end. 


122  SELF-PROPELLED  VEHICLES. 

No  means  has  yet  been  devised  to  insure  tires  used  on  very  high- 
speed machines. 

5.  Sharp  curves  or  excessive  side-slip  tend  to  produce  a  side 
pressure  that  is  concentrated  at  the  rim,  and,  in  proportion  to  the 
weight  of  the  car,  or  the  speed  at  which  it  is  driven,  are  liable 
to  result  in  cutting  of  the  case  tube.  Side  slipping  or  skidding 
is  largely  neutralized  in  cars  with  long  wheel-base,  but,  even 
with  this  desirable  structural  feature,  occasions  may  arise  in 
which  rim-cutting  results  from  sudden  turns.  Once  started,  a 
weak  point  is  developed  that  tends  to  increase  the  rent  under  all 
favorable  circumstances. 

Cracking  of  the  Walls. — If  a  tire  is  well  made  any  evidence 
of  cracking  of  the  case  tube  may  safely  be  attributed  to  driving 
with  insufficient  inflation.  As  the  result  of  a  puncture  or  other 
mishap,  all  the  air  may  be  exhausted,  causing  the  tire  to  be  com- 
pletely flattened  under  the  weight  of  the  vehicle.  If  this  does 
not  immediately  produce  cracking  of  the  case  tube,  it  is  a  rare 
good  fortune.  Long  continued  pressure  of  this  kind  will  in- 
fallibly tear  and  destroy  the  fabric. 

The  remedy  is,  of  course,  to  make  such  repairs  as  are  pos- 
sible at  the  time,  or  else  to  insert  a  new  air  tube.  If  no  extra 
air  tube  is  at  hand,  and  repairs  cannot  be  made  conveniently, 
the  best  makeshift  is  to  procure  sufficient  length  of  old  rope  to 
wind  around  the  circumference  of  the  wheel  inside  the  case  tube. 
This  may  be  done  by  jacking  up  the  wheel,  in  precisely  the  same 
fashion  as  if  to  insert  a  new  air  tube,  and  starting  to  wind  the 
rope  inside  the  case  tube,  entirely  around  the  circumference  of  the 
wheel,  until  no  more  can  be  inserted.  Care  should  be  taken  to 
leave  sufficient  clearance  to  insert  the  flange  of  the  tube  in  the 
clinch.  There  will  thus  be  afforded  sufficient  support  to  keep 
the  tire  from  being  flattened  for  more  than  half  its  diameter,  thus 
probably  saving  the  case  tube. 

Excessive  Wear  on  the  Walls  or  Tread. — Obviously  a  tire 
must  undergo  considerable  wear  in  course  of  use.  With  the  best 
possible  roads  and  the  highest  grade  of  rubber  a  more  or  less 


PNEUMATIC  TIRE  TROUBLES.  123 

rapid  deterioration  is  inevitable.  For  this,  of  course,  there  is  no 
remedy.  It  is  desirable,  however,  to  avoid  excessive  wear  when- 
ever possible. 

No  tire  should  be  used  after  the  rubber  at  the  tread  or  side 
walls  has  been  worn  down  to  the  fabric.  The  result  will  be  that 
the  structure  is  weakened,  offering  a  smaller  resistence  to  punc- 
ture and  tearing,  also  exposing  the  fibre  to  the  destructive  action 
of  water  and  other  corrodents,  not  to  mention  the  more  rapid 
wear  due  to  abradents,  sand,  etc. 

In  case  of  extraordinary  accidents  that  cut,  wear  or  tear  the 
walls,  the  case  tube  should  be  replaced  immediately,  in  order  to 
prevent  an  explosive  rending  of  the  air  tube.  This  latter  is  a 
far  more  serious  mishap  than  any  mere  puncture  or  even  cutting, 
and  very  frequently  precludes  the  possibility  of  repair. 

With  wheels  not  perfectly  parallel,  a  condition  to  be  found 
almost  exclusively  on  the  front  wheels,  there  is  liable  to  be  a 
very  great  wear  on  the  treads.  This  is  inevitable,  since  both 
wheels  must  slide  in  a  sidewise  direction,  quite  as  much  as  they 
can  rotate,  involving  an  unnecessary  waste  of  good  rubber. 

THE  CAUSE  OF  NON-PARALLEUSM  in  the  front  wheels  is  gen- 
erally to  be  found  in  a  short  or  bent  drag  link  between  the  steer- 
ing arms,  and  this  condition  should  be  carefully  searched  for 
before  other  troubles  are  suspected. 

SUDDEN  BRAKING,  although  sometimes  inevitable,  as  in  at- 
tempting to  avoid  running  down  a  foot  passenger  or  colliding 
with  any  object  in  the  road,  is  a  frequent  source  of  wear  on  rear- 
wheel  tires.  Causing  the  wheels  to  slide,  before  the  momentum 
of  the  car  is  overcome,  it  must  inevitably  cause  wear  at  the 
tread.  For  sake  of  preserving  the  tires,  if  for  no  other  reason, 
the  brake  of  an  automobile  should  be  thrown  on  as  gradually 
as  possible. 

DIRECT-ACTING  BRAKES,  or  shoe  brakes,  such  as  are  used 
on  heavy  horse  wagons  with  steel  tires,  are  mentioned  by  some 
authorities  as  destructive  to  the  treads  of  rubber  pneumatics. 
They  are  practically  never  used  on  automobiles  at  the  present 
day,  and  need  not  claim  much  of  our  attention.  It  may  be  said, 


124  SELF-PROPELLED  VEHICLES. 

however,  that  their  destructive  action  seems  to  be  in  inverse 
ratio  to  their  bearing  surface.  With  a  direct-acting  brake  of 
sufficient  surface  to  avoid  concentration  of  strain  on  a  limited 
area  of  tread,  the  wear  would  be  very  much  less.  One  authority 
states  that  he  has  used  such  a  shoe  brake  on  a  pneumatic  tricycle 
tire  for  several  years  without  harmful  results. 

DRIVING  AGAINST  CURBSTONES  is  often  the  occasion  of  wear 
upon  the  side  walls  of  a  tire.  If  frequently  repeated  the  fabric 
will  be  exposed,  and  the  destruction  of  the  tire  hastened.  A 
driver  should  always  avoid  contact  with  a  curbstone,  since  in- 
juries to  the  wheels  and  tires  are  by  no  means  warranted  by  the 
slight  advantage  gained  in  point  of  convenience  to  passengers. 

Chemical  Action. — Under  the  general  head  of  chemical  action 
we  may  include  causes  operating  to  corrode  or  rot  any  part  of  the 
tire.  Chemical  deterioration  may  affect  both  the  rubber  and  the 
fabric,  and  in  either  case  rapidly  wrecks  the  tire.  The  best  and 
strongest  tires  are  as  liable  to  chemical  injury  as  any  others. 

THE  RUBBER  of  a  tire  suffers  chemical  deterioration  from  the 
action  of  oil,  gasoline  or  acids.  These  substances,  whether  care- 
lessly dropped  upon  the  tire  or  present  at  any  part  of  the  roadway 
over  which  it  travels,  are  always  destructive  in  their  action.  If, 
therefore,  gasoline  or  oil  are  accidentally  spilled  upon  a  tire,  it 
should  be  wiped  clean  as  quickly  as  possible,  and  care  should 
be  exercised  not  to  allow  the  wheels  to  stand  in  accidental  puddles 
of  oil  on  the  table  floor.  Under  the  action  of  such  substances 
rubber  hardens,  losing  its  elasticity  and  tenacity,  and  developing 
a  tendency  to  wear  and  chip. 

STRONG  AND  STEADY  LIGHT,  as  well  as  high  or  changing  xc.ii- 
perature,  is  harmful  to  rubber.  After  a  tire  has  been  in  use 
for  some  time  it  is  less  liable  to  suffer  from  light  and  heat  than 
a  new  tire.  However,  no  tire,  new  or  old,  should  be  exposed  for 
extended  periods  in  blazing  sunlight  Particularly,  it  must  be 
said,  it  should  never  be  left  near  a  window,  so  that  the  sun  shines 
through  glass.  Sunlight,  under  such  conditions,  tends  to  harden 
the  rubber,  causing  it  to  develop  cracks.  Heat  acts  in  similai 
fashion,  although,  unless  excessive,  far  more  slowly. 


PNEUMATIC  TIRE  TROUBLES.  125 

EXTRA  TIRES  CARRIED  ON  A  CAR  should  always  be  kept  in  cases, 
such  as  are  provided  for  the  purpose  by  tire  dealers.  This  rule 
applies  with  particular  force  to  the  very  elastic  air  tubes,  which 
should  be  stored  in  bags  in  some  convenient  place  away  from  the 
light  and  heat  of  the  sun.  Many  expensive  air  tubes  have  been 
unnecessarily  ruined  by  lying  loose  in  the  wicker  baskets  at  the 
sides  of  the  tonneau. 

TIRES  IN  USE  are  not  as  liable  to  injury  from  sunlight  as  the 
extra  stored  tires,  for  the  reason  that  the  dust  and  mud  of  travel, 
while  not  directly  contributing  to  the  advantage  of  the  rubber, 
seem  to  neutralize  the  ill  effects  of  the  sun's  rays  in  an  efficient 
manner.  This  is  the  best  explanation  of  the  fact  that  used  tires 
are  less  liable  to  injury  than  new  ones. 

CHEMICAI,  INJURY  To  THE  FABRIC  or  thread  lining  of  a  tire 
consists  most  usually  in  rotting  from  the  presence  of  water  or 
dampness.  Injury  by  oil,  acid,  etc.,  is  much  more  remote.  On 
account  of  the  liability  of  the  fabric  to  be  rotted  by  moisture,  it 
is  particularly  desirable  that  the  rubber  be  not  allowed  to  wear 
away,  so  as  to  expose  it. 

DAMPNESS  acts  on  the  fabric  of  stored  tire  far  more  quickly 
than  water  will  act  on  canvas  wholly  immersed  in  it.  Water  has 
the  peculiar  faculty  of  penetrating  even  the  minutest  chinks  or 
punctures,  and  is  rapidly  absorbed  by  the  fibres  composing  the 
tire  fabric.  Only  one  result  can  follow :  the  fabric  will  be  broken 
down  and  the  case  tube  correspondingly  weakened.  Very  fre- 
quently tires  will  burst  from  this  cause,  after  being  stored  through 
the  winter  months. 

WHEN  IN  CONSTANT  USE  the  -fabric  of  a  tire  is  very  little  in 
danger  of  deterioration  from  water,  although  dampness  in  the 
stable  should  always  be  avoided.  A  tire  in  use,  however,  is  ex- 
posed to  an  ever  graver  danger:  a  cut  in  the  tread  of  the  case 
tube  may  admit  sand  or  mud,  which,  working  under  the  outer 
layer  of  rubber,  will  form  a  pocket,  where  water  may  collect  and 
begin  work  on  the  fabric.  Any  sign  of  a  cut  or  a  blister — as 
lumps  covering  sand  or  mud  are  called — should  warn  the  driver 
that  the  tire  needs  repair. 


CHAPTER  TWELVE. 

CARE  OF  PNEUMATIC  TIRES. 

Dimensions  of  Pneumatic  Tires. — Nearly  the  most  import- 
ant consideration  in  securing  the  best  service  from  pneumatic 
tires  is  that  they  should  be  of  sufficiently  large  dimensions  for 
the  load  they  are  intended  to  carry.  A  large  part  of  the 
troubles  with  tires,  so  conspicuous  in  former  days,  was  due 
principally  to  the  fact  that  they  were  too  small  for  their  loads. 
That  they  should  be  sufficiently  inflated  is  also  important. 
The  proper  dimensions  and  air-pressures  for  double-tube  tires, 
as  given  by  Michelin  and  other  authorities,  are  found,  as  fol- 
lows: 

For  loads  between  350  pounds  and  a  maximum  of  600  pounds 
per  wheel,  2.\  inches  diameter,  inflation  pressure,  50  pounds. 

For  loads  between  440  and  660  pounds  per  wheel,  3^  inches 
diameter,  inflation,  70  pounds. 

For  loads  between  550  and  990  pounds  per  wheel,  3^2  inches 
diameter,  inflation,  71  to  78  pounds. 

For  loads  between  660  and  1140  pounds  per  wheel,  4  inches 
diameter,  inflation,  71  to  78  pounds. 

For  loads  between  880  and  1320  pounds  per  wheel,  4^  inches 
diameter,  inflation  71  to  78  pounds. 

For  loads  between  noo  and  1650  pounds  per  wheel,  5*'2 
inches  diameter,  inflation,  71  to  85  pounds. 

The  inflation  pressure  may  be  indicated  by  pressure  gauges, 
such  as  are  furnished  by  some  supply  houses,  but  may  be 
judged  sufficient  when  the  tire  stands  firm  under  the  load.  A 
tire  too  small  for  the  load  will  likely  burst  under  pressure 
sufficient  to  render  it  firm. 

Care  of  Tires. — In  addition  to  the  several  principles  stated 
in  the  foregoing  chapter,  it  is  necessary  to  dwell  but  little  on 

186 


CARE  OF  PNEUMATIC  TIRES. 


127 


the  matter  of  caring  for  tires,  so  as  to  prevent,  as  far  as 
possible,  the  common  mishaps. 

1.  A  tire  of  proper  size  for  the  load  carried,  if  kept  properly 
inflated,  is  less  liable  to  puncture  than  when  allowed  to  become 
soft. 

2.  It  is  undesirable  to  overload  a  car,  so  as  to  bring  more 
than  the  maximum  pressure,  as  given  above,  upon  each  wheel. 
The  rest  of  the  machinery  may  endure  it:  the  tires  will  suffer. 


FIG.  101. 


FIG.  103.  FIG.  104. 

FIGS.  101-104.— Showing  successive  stages  in  the  removal  of  the  shoe  or  case-tube  of  a 
clincher  pneumatic  tire  by  the  insertion  of  a  tire  tool. 

This  is  one  very  excellent  reason  why  pneumatic  tires  may 
not  be  used  on  commercial  automobiles. 

3.  Excessive  speeds  are  made  possible — at  least  in  the  pres- 
ent stage  of  automobile  design — by  the  use  of  pneumatic  tires. 
The  inevitable  consequence,  however,  is  the  rapid  destruction 
of  the  tires.  Over-speeding  is  in  this  respect  equivalent  to 
overloading. 


128 


SELF-PROPELLED  VEHICLES. 


4.  Sudden  braking,  which  causes  the  tires  to  drag  by  re- 
straining the  rotation  of  the  wheels,  should  be  avoided,  when- 
ever possible.     Tires  so  treated  wear  and  tear  rapidly. 

5.  Sudden,  or  short,  turns,  by  distorting,  or  straining  the 
tires,  often  results  in  tearing  out  and  destruction. 

6.  A  tire  should  never  be  allowed  to  rub  against  a  curb  stone 
or  other  low  ridge.     Running  in  a  street  car  track  is  not  the 
best  practice,  as  it  sometimes  results  in  undue  wear  upon  the 
tire  treads,  and  occasionally  causes  cutting  of  the  walls. 

7.  Any  evidence  of  wearing  or  tearing  of  the  tread  or  case 
tube  should  lead  to  speedy  repair.     Tears  in  the  outer  rubber 
cover  generally  increase  in  size,  allowing  sand  and  moisture 


FIG.  105.  FIG.  1C6. 

FIGS.  105-106. — Showing  method  of  removing  the  case  tube  with  two  levers. 

to  work  in,  forming  "blisters,"  injuring  the  fabric  and  tearing 
off  the  outer  layer  of  rubber.  It  is  well  to  have  any  tear,  small 
or  large,  vulcanized  as  soon  as  possible,  thus  saving  further 
trouble  and  expense.  A  new  tread  should  be  vulcanized  on 
before  the  fabric  of  a  tire  is  exposed. 

8.  Never  allow  a  tire  on  a  vehicle  to  become  deflated.     If  it 
leaks,  remove  it  for  repair. 

9.  Particular  care  should  be  exercised,  in  removing  and  re- 
turning case  tubes,  not  to  rip  or  pinch  the  air  tube,  either  with 
the  tire  tool  or  between  the  ends  of  the  wall,  or  under  the  clips. 

Repair  of  Tires. — Formerly  books  treating  of  tires  included 
explicit  directions  for  repairing  punctured  and  injured  tires. 


CARE  OF  PNEUMATIC  TIRES. 


Most  of  the  rules  and  directions  then  given  are  out  of  date 
at  the  present  day.  Several  reasons  may  be  assigned  for  this 
statement: 

i.  The  greater  weight  of  the  vehicles  now  in  use  causes 
considerable  heating  within  the  tire,  particularly  when  the 
fabric  is  not  securely  united  with  the  rubber  in  the  case  tube, 
or  when  it  rips  and  tears  in  the  tread.  Often  the  mere  move- 
ment of  the  tire  generates  considerable  heat.  This  condition 
naturally  destroys  the  effect  of  most  rubber  cements,  such 
as  are  used  for  attaching  patches  to  the  inner  tube,  or  for 
securing  plugs  in  the  case  tube. 


FIG.  107.  FIG.  108. 

FIGS.  107-103.— Showing  method  of  removing  the  air  tube  with  a  single  (stepped) 
lever. 

2.  The  work  of  repairing  an  air  tube  is  altogether  too  deli- 
cate an  operation  to  be  undertaken  by  any  amateur.     This 
is  particularly  true  of  large  tubes  intended  to  contain  high 
pressures. 

3.  Experience  warrants  the  statement  that  the  common  run 
of  plugs,  patches,  foolish  tire  bands  and   all  other   repairs 
effected  by  the  use  of  cement  are  worse  than  useless  for  pres- 
ent-day tires.     Only  vulcanizing  can  effectually  remedy  dam- 


130 


SELF-PROPELLED    VEHICLES. 


FIG.  100. 


Fin.  :()!).\. 


Fi.i.  KlOn. 


FIG.  110. 


FIG.  111. 


FIG.  112. 


FIG.  113. 


FIG.  114. 


FIG.  115. 


.  109-115.— Diagrams  of  various  mishaps  to  pneumatic  tires.  Fig.  109  shows  the 
air  tube  resting  over  a  perfectly  fitting  chaplet  head ;  Figs .  109A  and  109s,  the 
effects  of  poorly  fitting  chaplets,  showing  liability  to  pinching  of  the  air  tube; 
Fig.  110,  air  tube  pinched  under  the  edge  of  case  tube ;  Fig.  Ill,  air  tube  pinched 
by  attempt  to  pull  down  chaplet — in  both  the*e  cases  the  air  tube  is  not  suffi- 
ciently inflated  while  attaching  the  case  tube;  Figs.  112  and  l!5,  the  right  and 
wrong  way  to  raise  the  edge  of  the  case  tube  over  the  clinch ;  Figs.  113  and  114, 
two  ways  in  which  the  air  tube  may  be  nipped  by  allowing  the  tire  tool  to  pene- 
trate too  far. 


CAKE  OP  PNEUMATIC  TIRES. 


131 


age  encountered  in  any  form  of  tire.  Vulcanizing  should  al- 
ways be  done  by  a  person  thoroughly  acquainted  with  working 
rubber. 

An  effectual  method  of  guarding  against  disablement  from 
tire  accidents  is  to  carry  at  least  one  extra  case  tube,  and 
several  extra  air  tubes.  Both  varieties  of  extra  tube  should 
be  carefully  wrapped  and  protected  from  sunlight  and  moist- 
ure. Moisture  within  the  case  tube  will  soon  work  destruc- 
tion to  the.  air  tube. 


FIG.  lie.  FIG.  117. 

FIGS.  116-117.— Showing  method  of  removing  the  air  tube  with  a  double  lever. 

In  the  event  of  being  caught  with  no  extra  air  tube,  the 
damaged  tube  may  be  removed  from  the  case,  which  may  then 
be  filled  as  nearly  as  possible  with  a  coil  of  half-inch  rope, 
wound  around  the  rim,  and  stuffed  into  the  case  as  far  as  it 
can  be  done,  so  as  to  prevent  too  much  bending  of  the  walls. 
The  support  thus  formed  will  enable  the  case  to  be  used  at 
a  slow  speed,  until  the  return  home.  If  the  tire  is  a  clincher,  the 
process  of  stuffing  in  the  rope  is  tedious.  If  a  side-flange  tire  is 
used,  the  process  is  far  simpler. 


THIRTEEN 


TYPES    AND    MERITS    OF    AUTOMOBILES. 


Types  of  Automobiles. — Within  the  last  three  years  the  con- 
struction of  automobiles,  or  motor-propelled  road  vehicles  has 
been  greatly  modified  and  improved  in  a  number  of  particulars. 
The  troubles  that  were  previously  notable  are  now  very  nearly 
overcome,  and  in  the  case  of  steam,  electric  and  gasoline  car- 
riages alike  the  ideal  of  a  perfectly  practical  machine  is  rapidly 
being  approximated.  Neither  has  this  gradual  development  of 
the  ideal  vehicle  involved  any  such  radical  changes  as  some  super- 
ficial and  ill-informed  persons  have  confidently  predicted.  True 
to  the  statements  of  practical  experts,  the  leading  features — 
such  as  steering  and  compensating  apparatus,  rear-wheel  drive, 
resilient  tires,  and  several  other  features — have  remained  the 
same.  Only  the  details  have  been  altered  and  improved  in  the 
gradual  evolution  of  the  practical  out  of  the  experimental. 
Furthermore,  the  steady  tendency  is  toward  a  greater  uniformity 
of  design,  rather  than  toward  any  eccentric  or  novel  construc- 
tions ;  toward  a  perfecting  of  standard  constructions  already 
recognized,  rather  than  toward  anything  entirely  new  and  pe- 
culiar. 

In  another  respect  the  development  of  the  practical  road  car- 
riage is  notable:  and  that  is,  that  the  largely  increased  use  of  l!-.2 
self-propelled  vehicle  has  enabled  the  builders  to  afford  a  :d 
supply  every  new  device  leading  to  speed  and  safety.  This 
liberality  in  the  manufacture  of  the  well  known  types  has  been  a 
constant  spur  to  invention  to  meet  the  desires  of  purchasers — the 
result  being,  at  the  date  of  the  issue  of  this  edition  of  the  work, 
the  production  of  one  of  the  most  marvelous  mechanisms  the 
world  has  ever  seen. 

This  remark  relates  to  the  several  types  of  vehicles,  gasoline,  steam  and 
electric.  Each  type  has  its  advantages  and  disadvantages.  The  fact  that 
one  form  of  power  is  more  extensively  used  than  another  should  not 

182 


TYPES   AND    MERITS    OP   AUTOMOBILES.  133 

influence  the  intending  purchaser  any  more  than  the  talk  of  interested 
parties.  He  should  be  guided  by  his  mechanical  inclinations  and  by  the 
particular  service  that  he  will  require  of  the  machine.  For  instance,  while 
an  electric  vehicle  is  very  desirable  for  city  use  or  in  localities  having 
good  roads  and  battery  charging  facilities,  a  steamer  is  well  adapted  to 
touring  on  all  kinds  of  roads  and  steep  hills.  While  the  radius  of  travel 
on  one  filling  of  fuel  tanks  is  generally  greater  for  the  gasoline  car,  the 
steamer  can  use  as  fuel  both  gasoline  and  kerosene. 

Advantages  Analyzed. — In  a  recent  number  of  a  well-known 
automobile  journal  (Motor,  New  York),  the  several  advantages 
of  the  three  types  of  machine  are  set  forth  by  prominent  experts. 

Speaking  for  the  steam  vehicle,  Windsor  T.  White  specifies 
the  following  twelve  advantages:  (i)  Practical  absence  of  jar  and 
noise;  (2)  ease  of  control — throttling  instead  of  gear  shifting  by 
levers;  (3)  absence  of  gearing  between  the  engine  and  the  drive 
axle;  (4)  flexibility  of  the  steam  engine,  permitting  any  speed, 
from  highest  to  lowest,  with  nearly  even  power  efficiency;  (5) 
continuous  application  of  power  in  each  cylinder,  instead  of  a 
power  stroke  in  each  two  revolutions,  as  with  the  four-cycle 
gasoline  engine;  (6)  ease  of  lubrication  in  the  comparative- 
ly cool  cylinder,  and  absence  of  trouble  from  over  -  oiling ; 
(7)  the  fact  that  the  steam  engine  is  better  understood  by  the 
average  man  than  either  of  the  other  motive  powers;  (8)  from 
this  reason,  the  greater  ease  of  having  roadside  repairs  made ; 
(9)  a  combination  of  flash  generator,  automatic  fuel  regula- 
tion, compound  engine  and  direct  drive  gives  the  most  satis- 
factory machine  for  inexpert  operators ;  ( 10)  certain  and  invari- 
able automatic  regulation  dependent  solely  on  the  physical  prop- 
erties of  varying  temperature  and  pressure;  (n)  complete  elim- 
ination of  boiler  troubles,  scaling,  etc.,  by  the  use  of  the  flash 
generator;  (12)  complete  immunity  from  burning  out,  with  the 
combination  of  flash  generator  and  thermostatic  regulation. 

Mr.  White  is  speaking,  of  course,  of  a  carriage  using  the  flash- 
line  system  of  generation,  as  embodied  in  the  machines  built  by 
his  company,  which  have  proved  of  the  greatest  advantage  for 
this  purpose  since  the  time  of  Serpollet's  first  invention  of  this 
apparatus  in  1889.  With  other  types  of  generator  and  regulator 
the  advantages  are  less  conspicuous.  Mervyn  O'Gorman,  an 
English  authority,  states  the  case  of  the  average  steam  carriage 
from  both  sides.  As  ten  advantages :  (i)  Absence  of  speed  gears ; 


134  SELF-PROPELLED   VEHICLES. 

(2)  saving  of  wear,  tear  and  noise;  (3)  high  power-outputs  for 
short  periods  for  climbing  hills  and  traveling  on  rough  roads; 
(4)  greater  speed  uphill,  and  greater  average  speed  for  original 
cost;  (5)  proportionate  fuel  consumption  and  power  efficiency; 

(6)  cleanliness  equal  to  petrol  motors;  (7)  absence  of  the  trou- 
blesome ignition  system,  as  on  petrol  motors;   (8)   absence  of 
exhaust  noises,  back-shots,  pre-ignition,  etc. ;   (9)   cheapness  in 
first  cost;  (10)  starting  without  cranking,  therefore  stillness  of 
the  car  in  standing.    As  sixteen  disadvantages :  ( i )  The  need  of 
extinguishing   the   fire    during   stoppages;    (2)    the    consequent 
trouble  of  re-igniting  the  burner  5(3)  the  great  loss  of  fuel,  due  to 
not  extinguishing;  (4)  the  need  for  greater  attention,  owing  to 
the  number  of  adjustments  not  automatic;  (5)  limited  capacity 
for  carrying  fuel  and  water  supply ;  (6)  heavy  fuel  consumption, 
generally  twice  that  of  gasoline  carriages  of  the  same  power; 

(7)  heavy  water  consumption,  and  the  need  for  constant  refills; 

(8)  fouling  of  the  boiler  tubes — in  some  types;  (9)  vitiation  of 
the  air  by  burned  products  in  greater  volume  than  with  gasoline 
motors;  (10)  loss  of  time  in  starting  from  a  cold  boiler;  (n) 
greater  dangers  from  neglect,  such  as  seizing  and  heating  from 
insufficient  lubrication,  grave  consequences  in  failure  of  water 
system,  priming  from  high  water  and  consequent  knocking  of 
the  pistons,  evil  effects  of  feeding  oil  into  any  type  of  boiler  or 
generator,   clogging  of  valves  or   failure  of  pumps;    (12)    the 
troubles,  due  to  wind  blowing  down  upon  the  fire;  (13)  stoppage 
of  safety  valves ;  ( 14)  necessity  of  using  soft  water  for  boilers ; 
(15)  trouble  of  cleaning  the  flues;  (16)  issue  of  visible  steam 
mixed  with  oil  liable  to  stain  clothes. 

Setting  forth  the  advantages  of  the  gasoline  carriage,  Elmer 
Apperson  enumerates  the  following  twelve  points:  (i)  Availa- 
bility of  fuel,  readily  obtainable  anywhere;  (2)  convenience  in 
renewing  the  supply,  no  fire  being  present  that  must  be  extin- 
guished;  (3)  economy  of  fuel,  owing  (a)  to  none  being  used 
when  the  machine  is  standing,  (b)  to  the  small  amount  used  when 
running  light,  (c)  to  the  high  efficiency  of  the  gasoline  engine 
— twenty-five  or  thirty  per  cent,  as  against  ten  per  cent,  for  the 
steam  engine,  and  less  for  the  electric  motor;  (4)  perfect  throt- 
tling system  for  changing  the  speed  and  power  ratios:  (5)  noise- 
lessness,  as  achieved  in  the  later  types  of  motor;  (6)  ease  of  using 
in  winter  with  non-freezing  jacket  solutions;  (7)  the  absence  of 


TYPES   AND   MERITS   OF   AUTOMOBILES,  135 

indicating  devices  to  distract  the  mind  of  the  operator;  (8)  ab- 
sence of  constant  fire,  as  in  a  steam  machine  to  "make  a  volcano 
of  the  slightest  leak"  ;  (9)  rareness  of  total  disablement,  as  against 
steam  or  gasoline  machines ;  ( 10)  extended  travel  radius,  gasoline 
machines  having  been  run  1,000  miles  without  a  stop,  as  against 
the  record  of  100  miles  for  a  steamer,  and  the  average  of  30  or 
40  miles  per  charge  for  the  electric;  (u)  the  greater  perfection 
of  the  gasoline  machine,  on  account  of  the  thought  and  labor 
expended  in  its  development;  (12)  that  it  can  be  built  with  any 
style  of  body,  for  any  kind  of  service,  and  holds  all  records  for 
speed  and  endurance. 

The  claims  of  the  electric  carriage  are  set  forth  by  Walter  C. 
Baker  under  the  following  twelve  heads:  (i)  The  superior  ma- 
terial of  the  electric  carriage,  together  with  its  durability  and 
attractiveness;  (2)  the  speed  range,  greater  than  a  horse  at  low 
speed  and  within  legal  limits  at  top  speed;  (3)  the  small  care 
required  in  comparison  with  other  types  of  power,  the  smallest 
attention  yielding  the  best  results — the  battery  alone  demanding 
particular  care;  (4)  the  ideal  source  of  energy  found  in  the  stor- 
age batten-,  which  is  compact,  clean,  safe,  and  able  to  yield  in- 
stantly to  the  will  of  the  operator;  (5)  freedom  from  noise,  odor 
or  vibration;  (6)  with  all  mechanical  parts  rotating,  anti-friction 
bearings  may  be  used  throughout,  enabling  great  results  from 
little  power;  (7)  the  slight  physical  effort  required  to  manage 
it;  (8)  absence  of  oil,  fire,  water  and  pumps  leaves  nothing  to 
freeze,  burn,  or  explode,  and  requires  no  pumping  at  the  start; 
(9)  absence  of  lubricants  renders  it  clean;  (10)  safety  for  ladies 
and  convenience  for  short  tours :  ( 1 1 )  small  number  of  occasions 
for  failure  to  run ;  (12)  a  single  lever  to  control  the  motive  power, 
and  another  for  steering,  rendering  it  the  simplest  of  all  to  man- 
age. 


CHAPTER    FOURTEEN. 
THE  THEORY  OF  HEAT  ENGINES. 

Power  Derived  from  Heat. — Both  steam  and  gas  engines  are 
forms  of  heat  motor;  since  both  operate  by  means  of  the  ex- 
pansive energy  of  gases,  which  have  been  subjected  to  the  action 
of  heat.  A  permanent  gas,  or  the  vapor  from  a  liquid  or  solid 
substance,  when  exposed  to  heat  tends  to  expand,  and,  in  expand- 
ing, exerts  an  active  pressure  in  all  directions.  Thus,  if  a  gas, 
or  a  readily  volatized  liquid,  like  water  or  alcohol,  contained  in  a 
corked  vessel,  be  exposed  to  heat,  the  expansion  will  be  exhibited 
in  the  expulsion  of  the  cork.  In  this  fact  it  demonstrated  the 
principle,  on  which  all  forms  of  heat  engine  operate — that  heat 
may  be  transformed  into  mechanical  energy  through  its  effects 
on  liquids  and  gases,  promoting  the  change  from  fluid  to  gaseous 
state  and  then  increasing  the  volume  of  the  gas.  No  state  of  mat- 
ter is  entirely  permanent,  and,  as  a  general  rule,  the  absorption 
of  a  sufficient  quantity  of  heat  results  in  liquefying  a  solid,  and  in 
vaporizing  a  liquid.  Gases  subjected  to  heat,  either  when  ignited, 
as  with  inflammable  gases,  or  merely  heated  as  with  separated 
steam,  tend  to  assume  greater  volumes  so  long  as  the  temperature 
is  not  allowed  to  fall.  On  the  other  hand,  modern  science  has 
succeeded  in  producing  liquid  air  and  liquid  carbonic  acid  gas 
by  the  combination  of  extremely  high  pressures  and  extremely 
low  temperatures.  It  is  sufficient  to  say  that  no  pressure  has  yet 
been  found  sufficiently  high  to  liquefy  air,  without  the  cooperation 
of  a  temperature  commensurately  low.  Conversely,  also,  no 
known  degree  of  cold  can  produce  this  effect,  apart  from  a  high 
pressure  acting  at  the  same  time. 

Principles  of  Pressure  and  Temperature  in  Gases. — A  lead- 
ing property  of  gases  is  that,  the  temperature  remaining  the 
same,  an  increase  in  volume  involves  a  corresponding  uecrease  in 

136 


THEOR  Y  OF  HE  A  T  ENGINES  137 

pressure,  and,  that  to  maintain  even  a  constant  pressure  in  an 
expanding  gas,  the  temperature  must  be  raised  on  a  steadily  in- 
creasing ratio.  In  other  words,  a  given  cubic  content  of  expand- 
ing gas,  at  a  constant  temperature,  shows  a  lower  pressure  per 
square  inch  as  the  expansion  progresses,  and,  in  order  to  obtain 
a  given  total  original  efficient  pressure  the  cubic  content  of  the 
cylinder  must  increase  with  the  expansion.  On  the  other  hand, 
if  a  given  cubic  content  of  gas  be  compressed  to  half  its  normal 
volume,  without  involving  an  accompanying  increase  in  temper- 
ature, the  pressure  is  doubled.  In  either  case,  an  undue  increase 
of  temperature  operates  to  neutralize  the  stated  principle. 
From  these  facts  we  may  deduce  the  principles  that: 

1.  The  inherent  pressure  of  a  gas  varies  inversely  with  the 
volume  and  directly  with  the  temperature. 

2.  The  volume  of  a  gas  varies  inversely  with  the  pressure  and 
directly  with  the  temperature. 

3.  The  inherent  temperature  of  a  gas  varies  directly  with  the 
pressure  and  inversely  with  the  volume. 

To  state  these  principles  in  another  way,  we  may  say: 

1.  An  increased  pressure  involves  a  decreased  volume  or  an 
increased  temperature. 

2.  An  increased  volume  involves  a  decreased  pressure  or  an 
increased  temperature. 

3.  An  increased  temperature  involves  an  increased  volume  and 
an  increased  pressure. 

As  the  operative  conditions  in  a  heat  engine  are  immensely 
irregular  no  formulae  can  precisely  express  the  proper  tem- 
perature, volume  or  pressure  to  show  working  conditions.  Since, 
however,  the  attributes  of  the  gas  at  various  points  in  the  cycle 
are  in  direct  proportion  to  the  dimensions  of  the  cylinder,  the 
1ength  of  the  stroke,  the  cubic  content  of  the  clearance,  and  other 
familiar  physical  and  mechanical  conditions,  very  satisfactory 
figures  may  be  found  to  express  the  power  and  capacity  of  any 
particular  engine. 


138  SELF-PROPELLED   VEHICLES. 

The  Law  of  Pressure  and  Volume  of  Gases. — The  physicaJ 
properties  of  gases  in  general  are  defined  by  two  familiar  laws 
— the  first  defining  the  degrees  of  volume  and  pressure  at  con- 
stantly maintained  temperatures;  the  second,  the  ratio  of  expan- 
sion at  a  constantly  increasing  temperature.  The  first,  known  as 
Boyle's  Law,  states  that 

THE  VOLUME  OF  A  GAS  VARIES  INVERSELY  AS  THE  PRESSURE,  SO 
LONG  AS  THE  TEMPERATURE  REMAINS  THE  SAME,  OR,  THE  PRESS- 
URE OP  A  GAS  IS  PROPORTIONAL  TO  ITS  DENSITY. 

This  law  has  frequently  been  illustrated  by  the  following  ex- 
periment : 

If  we  take  a  hollow  cylinder,  such  as  is  used  on  steam  engines, 
having  a  piston  sliding  airtight  in  its  length,  we  will  find  that  the 
contained,  air  or  other  gas,  is  compressed  in  front  of  the  piston 
as  it  is  forced  from  one  end  toward  the  other  of  the  base,  and  that 
this  air,  or  gas,  exerts  a  pressure  which  increases  in  ratio  as  the 
volume  is  diminished.  This  fact  may  be  shown  by  inserting  in 
the  wall  of  the  cylinder  a  tube  containing  an  airtight  piston,  upon 
which  bears  a  spiral  spring  holding  it  normally,  as  at  A  in  the 
accompanying  diagram;  the  pressure  there  being  supposedly 
equal  on  both  sides  of  the  piston,  or  equivalent  to  15  pounds  per 
square  inch.  If,  now,  the  area  of  this  small  piston  be  exactly  one 
square  inch,  and  the  spring  of  such  a  tension  as  to  move  upward 
through  one  of  the  spaces  between  the  lines  on  the  diagram  be- 
hind the  large  cylinder  with  each  ten  pounds  of  added  pressure 
from  below,  the  result  will  be  as  follows :  When  the  piston  of  the 
large  cylinder  has  been  pushed  through  one-half  its  length,  the 
depression  of  the  spring  in  the  smaller  one  will  show  that  the 
pressure  is  just  twice  what  it  was  at  the  start,  or  30  pounds.  At 
three-quarters  the  stroke  it  will  show  sixty  pounds,  and  at  seven- 
eighths,  120  pounds.  If  the  four  smaller  cylinders  be  arranged 
in  the  wall  of  the  cylinder,  as  in  the  diagram,  the  difference  in 
pressure  at  these  several  points  may  be  graphically  represented. 
Then  a  curve,  drawn  so  as  to  pass  through  the  center  of  each 
of  the  smaller  pistons,  will  give  an  accurate  average  of  presswe 


THEOR  Y  OF  HE  A  T  ENGINES. 


189 


for  every  position  of  the  large  piston.  On  the  other  hand,  as 
under  the  operative  conditions  in  a  steam  engine,  it  will  represent 
the  "curve  of  expansion,"  or  the  decrease  in  pressure  from 


r 


A 


°'Q.  118.— Diagrammatic  Section  of  a  Cylinder.  Illustrating  the  compression  and 
expansio"  of  gases.  This  cylinder  ii  filled  with  air  at  atmospheric  pressure  which 
represf-nts  a  uniform  14.7  pounds  t"  the  square  inch  behind  the  piston,  as  shown 
by  the  position  of  the  piston  in  the  small  cylinder.  A.  When  the  piston  of  the 
large  cylinder  is  moved  through  half  the  length  of  the  stroke.  It  shows  30  pounds 
pressure,  as  shown  by  the  position  of  the  piston  In  small  cylinder,  B;  when  at 
three-quarters  stroke,  60  p'  unds,  as  shown  by  the  position  of  the  piston,  C  t  when 
at  seven -eighths  stroke,  1-0  pounds,  as  shown  by  position  of  piston,  D.  At  full 
stroke  it  would  be  240  pounds,  the  diagram  behind  the  small  piston  giving  the 
compression  curve  from  15  to  240. 

the  moment  of  "cut-off,"  when  the  inlet  valve  is  closed  to  the  end 
of  the  stroke,  when  the  exhaust  valve  is  opened.  If,  therefore, 
steam  be  fed  into  the  cylinder  at  200  pounds  pressure  per  square 


140  SELF-PROPELLED  VEHICLES. 

inch,  and  the  inlet  be  closed  when  the  piston  has  traversed  one 
eight  of  the  stroke,  the  pressure  will  stand  at  100  pounds  on 
quarter-stroke ;  at  50  pounds  on  half  stroke,  and,  at  25  pounds 
on  the  point  of  completed  stroke,  which  shows  that  it  is  expanded 
eight  times. 

Very  similar  conditions  exist  in  the  cylinder  of  a  gas  engine, 
as  will  be  shown- later.  Here,  the  expansion  of  the  gas  in  cylinder 
is  estimated  from  the  moment  of  maximum  pressure,  when  the 
fuel  charge  has  reached  the  height  of  its  temperature,  due  to  its 
ignition  b>  electric  spark  or  other  source  of  firing. 

In  both  the  cases  in  the  diagram,  the  temperature  is  supposed  to 
remain  constant,  while  the  pressure  increases,  on  the  one  hand,  or 
decreases  on  the  other.  Such  compression  and  expansion  would 
be  entirely  isothermal,  that  is,  it  would  take  place  at  a  constant 
temperature. 

The  Temperature  and  Volume  of  Gases. — The  "second  law 

of  gases,"  called  Charles  or  Gay  Lussac's  law,  states  that 

AT  CONSTANT  PRESSURE  THE  VOLUME  OF  A  GAS  VARIES  WITH 
THE  TEMPERATURE,  THE  INCREASE  BEING  IN  PROPORTION  TO  THE 
CHANGE  OF  TEMPERATURE  AND  THE  VOLUME  OF  THE  GAS  AT  ZERO. 
By  actual  experiment  it  has  been  ascertained  that  a  gas  in- 
creases on  a  ratio  of  i-493d  part  of  its  volume  at  32°  Fahrenheit, 
with  each  additional  degree  added  to  its  temperature.  This  places 
the  "absolute  zero,"  or  the  point  at  which  a  gas  would  assume 
its  greatest  possible  density  at  —  461°,  Fahrenheit,  or  — 273°, 
Centigrade. 

Absolute  Figures  for  Temperature. — In  temperature  and 
pressure  calculations  for  heat  engines,  it  is  customary  to  use 
absolute  figures,  so  called,  as  based  upon  the  data  just  given. 
Thus,  the  absolute  temperature  is  the  sum  of  the  sensible  ther- 
mometric  temperature  and  the  constant  461.  This  latter  figure, 
which  is  more  properly  expressed  as  460.66,  represents  the  total 
number  of  degrees  on  the  Fahrenheit  scale  frona  32°  below  the 


THEOR  Y  OF  HE  A  T  ENGINES.  141 

freezing  point  of  water  to  absolute  zero  of  temperature,  as  cal- 
culated by  the  expansion  ratio  of  gases.  Thus  in  calculating  tem- 
peratures, we  count  from  absolute  zero;  instead  of  64°,  writing 
525°,  and  instead  of  °32,  writing  493°,  or,  more  correctly, 
492.66°.  The  utility  of  this  system  lies  in  the  fact  that,  as  a  gas 
has  been  found  to  expand  by  1-273  °f  its  original  volume  for  each 
degree,  centigrade,  or  by  1-461  for  each  degree,  Fahrenheit,  of 
increased  temperature,  we  have  by  the  use  of  absolute  figures  an 
approximate  expression  for  both  increased  heat  and  increased 
volume  in  the  same  number. 

The  absolute  zero  is  the  point  of  theoretically  complete  stability 
of  a  gas. 

Absolute  Figures  for  Pressure. — Similarly,  the  absolute 
pressure  is  given  as  the  sum  of  the  gauge  pressure  and  the  con- 
stant 15  (more  correctly  14.7),  representing  the  total  pressure 
above  zero  acting  against  atmosphere.  Since,  in  a  gauge,  or  in 
the  cylinder  of  a  heat  engine,  the  effective  power  is  acting  against 
the  pressure  of  the  atmosphere,  which  is  14.7  Ibs.  per  square  inch, 
the  recorded  pressure  represents  the  actual  pressure  less  14.7. 

The  pressure  and  temperature  of  a  gas  being  strictly  in  ratio,  it 
is  possible  to  determine  the  temperature,  approximately  at  least 
from  the  gauge  pressure.  The  correspondents  of  temperature  and 
pressure  for  various  gases  may  be  determined  by  knowledge  of 
their  physical  properties.  For  steam  they  have  been  completely 
tabulated,  as  shown  in  the  following  columns,  which  contain 
averages  by  several  authorities : 

Pressure.      Temperature.  Pressure.      Temperature.           Pressure.      Temperature 

15  Ibs.  —  212°  F.  55  Ibs.  —  288°  F.  100  Ibs.  —  330°  F. 

20  Ibs.  —  228°  F.  60  Ibs.  —  294°  F.  105  Ibs.  —  333°  F. 

25  Ibs.  —  241°  F.  65  Ibs.  —  299°  F.  120  Ibs.  —  343°  F. 

30  Ibs.  —  252°  F.  70  Ibs.  —  304°  F.  135  Ibs.  —  352°  F. 

35  Ibs.  —  261°  F.  75  Ibs.  —  309°  F.  150  Ibs.  —  362°  F. 

40  Ibs.  —  268°  F.  80  Ibs.  —  313°  F.  165  Ibs.  —  369°  F. 

45  Ibs.  —  275°  F.  85  Ibs.  —  316°  F.  180  Ibs.  —  375°  F. 

50  Ibs.  —  282°  F.  90  Ibs.  —  322°  F.  195  Ibs.  —  383°  F. 


143 


SELF-PROPELLED   VEHICLES. 


Determining  the  Temperature  from  the  Pressure. — Al- 
though saturated  steam,  or  steam  having  a  temperature  corre- 
sponding to  its  pressure,  is  not  a  perfect  gas,  the  operative  con- 
ditions in  a  steam  engine  are  fairly  typical  for  any  form  of  motor 
operating  through  the  expansive  effect  of  heat  upon  gases. 

In  order  to  explain  the  process  for  a  cylinder  expanding  i-io 
pound  of  steam  from  120  pounds  per  square  inch  pressure  to  at- 
mosphere. The  following  passage  quoted  from  Forney's  "Cat- 
echism of  the  Locomotive,"  is  sufficient: 

"If  the  piston  stand  at  the  point  shown  in  the  previous  figure,  and  i-io 
pound  of  water  be  put  into  the  cylinder,  and  heat  be  applied  to  it,  it  would 


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VlQ.  119.—  Diagram  showing  the  number  of  heat  units  required  to  raise  one-tcuth 
pound  of  steam  under  the  various  pressures  indicated  by  the  position  of  tLe 
piston,  at  full  stroke,  half  stroke  and  seven-eights  stroke.  In  using  this  diagram 

It  is  necessary  to  note  that  the  heat  units  are  calculated  from— 1°  Fahrenheit,  in- 
stead of  from  39°,  as  is  the  general  rule. 

be  necessary  to  heat  the  water  to  212°  before  it  would  boil.  To  represent 
this  heat,  the  vertical  line,  J'j  is  extended  below  the  horizontal  line,  AJ. 
To  heat  i-io  pound  of  water  to  212°  takes  21.2  units  of  heat, — since  one 
unit  of  heat  is  required  to  raise  one  pound  of  water  at  39°  Fahrenheit  to 
one  degree  above — which  is  laid  off  from  7  to  ]'  to  the  scale  represented 
by  the  horizontal  lines.  But  as  is  shown  in  the  table  in  the  appendix,  after 
the  water  begins  to  boil,  96.6  more  units  of  heat  must  be  added  to  it  to 
convert  it  all  into  steam  of  atmospheric  pressure.  This  number  of  units 
of  heat  is,  therefore,  laid  off  from  7  to  7.'  If  the  piston  be  moved  to  E, 
the  middle  of  the  cylinder,  and  i-io  pound  of  water  is  again  put  into  it, 
and  it  is  all  converted  into  steam,  it  will  have  a  pressure  of  30  pounds 
per  square  inch,  as  it  occupies  only  half  the  volume  that  the  same  quantity 


THEOR  Y  OF  HE  A  T  ENGINES.  143 

of  steam  did  before.  To  make  water  boil  under  a  pressure  of  30  pounds, 
it  must  be  heated  to  a  temperature  of  250.4°,  which  in  this  case  will  require 
25  units  of  heat,  which  is  laid  down  from  E  to  £'.  To  convert  the  water 
into  steam,  after  it  begins  to  boil,  will  require  93.9  more  units  of  heat, 
which  is  also  laid  down  from  E  to  E".  In  the  same  way  the  total  heat 
to  boil  and  convert  i-io  pound  of  water  into  steam  at  60  and  120  pounds 
pressure,  as  shown  in  the  appendix,  is  laid  down  on  C  C"  and  B  B",  and 
the  two  curves,  B'  C'  E'  J'  and  B"  C"  E"  J",  are  drawn  through  the  points 
which  have  been  laid  down.  The  vertical  distance  of  the  one  curve  from 
A  J  represents  the  heat  units  required  to  boil  i-io  pound  of  water  at  the 
pressures  indicated  by  the  curve  in  the  previous  figure,  and  the  vertical 
distance  of  the  second  curve  from  A  J  represents  the  total  units  of  heat 
required  to  convert  i-io  pound  of  water  into  steam  of  a  volume  indicated 
by  the  horizontal  distance  of  any  point  of  the  curve  from  A  A",  and  when 
pressure  is  indicated  by  the  expansion  curve  above.  This  curve  and  the 
heat  diagram  may  be  very  conveniently  combined  by  adding  the  latter 
below  the  vacuum  line  of  the  former.  The  relation  of  the  volume  pressure 
and  total  heat  is  thus  shown  very  clearly." 

Joule's   Law  of  Temperature   and   Pressure. — As  may  be 

readily  understood  from  what  has  already  been  said,  the  recog- 
nized principle  in  the  operation  of  all  forms  of  heat  engine  is  that 

THE  WORK-PRODUCING  OR  DYNAMIC  PROPERTY  OF  A  GAS  DE- 
PENDS SOLELY  UPON  ITS  TEMPERATURE. 

This  is,  substantially,  a  statement  of  Joule's  law,  which  com- 
pares the  temperature  of  a  gas,  enabling  it  to  exert  a  certain 
amount  of  power,  to  the  stored  energy  represented  in  a  body  of 
a  certain  weight  raised  to  a  certain  height  above  the  ground.  The 
body,  in  falling  under  the  force  of  gravity,  obtains  a  certain  de- 
gree of  acceleration,  constantly  increasing,  by  which  the  weight 
falling  through  the  given  distance  is  transformed  into  a  force 
capable  of  producing  a  commensurate  effect  of  impact  on  reaching 
the  earth's  surface.  This  potential  energy  of  a  substance,  rep- 
resented either  by  an  acquired  temperature  or  some  analogous 
physical  condition,  which,  under  favorable  circumstances,  would 
enable  the  production  of  a  definite  amount  of  work,  is  known  as 
"entropy."  Could  the  whole  power  of  a  heated  gas  be  realized  in 
its  expansion — which  is  to  say,  could  its  expansion  be  perfectly 
"adiabatic,"  or  "isentropic,"  involving  neither  gain  nor  loss  of 


144  SELF-PROPELLED   VEHICLES. 

heat  in  the  process — we  should  have  a  theoretically  perfect  ex- 
pansion curve  on  every  practical  heat  engine.  This  is  impossible, 
however,  with  the  best  arrangements  yet  contrived.  Hence  it  is 
that  the  expansion  curves  of  all  engines  fall  far  below  what  is 
demanded  by  theory  from  the  original  temperature  and  pressure 
of  the  steam,  which  involves  that  the  final  volume  and  the  actual 
work  .accomplished  are  correspondingly  diminished. 

To  quote  from  an  authority  on  steam  engines,  "as  we  cannot 
take  into  consideration  all  the  conditions  which  govern  and 
modify  the  cycle  of  any  motor,  the  usual  practice  is  to  calculate 
the  power  on  the  assumption  that  all  theoretical  conditions  are 
complied  with,  and  then  modify  the  result  by  a  certain  co-efficient 
of  efficiency  which  practice  has  established  for  the  particular 
type  of  motor  under  consideration." 

The  Steam  Engine  Indicator  and  Its  Diagram. — The  action 
of  the  small  cylinders  containing  springs  and  pistons  as  explained 
in  connection  with  Fig.  118,  very  well  illustrates  the  operation 
of  the  steam  engine  indicator  in  tracing  the  diagram,  or  "card," 
which  reveals  so  much  on  the  conditions  within  the  cylinder.  The 
simplest  form  of  this  instrument  has  a  cylinder  identical  with 
those  shown  in  the  figure,  except  for  a  pencil  carried  on  the  upper- 
most end  of  the  piston  rod,  and  bearing  upon  a  suitable  tablet, 
which  is  moved  backward  and  forward  with  the  stroke  of  the 
steam  piston.  This  is  done  by  attaching  the  long  arm  of  a  re- 
ducing lever  to  the  cross  head,  and  the  shorter  arm  to  a  link -bar, 
which  holds  the  card,  or  tablet,  to  be  inscribed.  The  line  traced 
by  the  pencil  point  will  rise  or  fall,  as  the  pressure  within  the 
small  cylinder  is  increased  or  reduced.  The  several  forms  of  the 
indicator  most  often  used  at  the  present  day  have  a  rotatable 
drum,  which  is  attached  by  a  cord  to  the  short  arm  of  the  reduc- 
ing lever,  so  as  to  be  turned  in  one  direction ;  being  moved  in  the 
other  direction  by  a  contained  spring,  which  rewinds  the  cord, 
so  soon  as  the  lever  arm  moves  backward.  Thus  the  records  of 
a  great  number  of  strokes  may  be  taken  on  one  sheet  of  paper. 


THEOR  Y  OF  HE  A  T  ENGINES.  145 

The  records  thus  made,  by  knowing  the  dimensions  of  the  cyl- 
inder and  the  tension,  or  resisting  strength,  of  the  steam-actu- 
ated spring,  may  be  very  accurately  calculated  for  the  entire 
cycle  of  the  engine. 

The  Indicator  Diagram  and  the  Steam  Engine  Cycle. — The 

operative  efficiency  of  an  engine  may  be  very  well  determined 
from  the  indicator  diagram,  which  gives  a  pictorial  representation 
of  the  internal  conditions  throughout  the  entire  cycle  of  opera- 
tions. As  given  by  a  noted  authority,  already  quoted,  the  steam 
engine  diagram  tells  eleven  different  things  essential  to  be  known : 


f 

FIG.  120.— Diagram  of  the  Cycle  of  a  Steam  Engine. 

1.  It  gives  the  initial  pressure,  or  the  pressure  at  beginning  of 
the  stroke. 

2.  It  tells  whether  the  pressure  is  increased  or  diminished  dur- 
ing the  period  of  admission. 

3.  It  gives  the  point  of  cut-off,  when  the  valve  is  closed  and 
expansion  begins. 

4.  It  indicates  the  rate  and  pressure  of  expansion  during  the 
whole  period  of  expansion. 

5.  It  gives  the  "point  of  release,"  when  the  exhaust  is  opened. 

6.  It  shows  the  rapidity  of  the  exhaust. 

7.  It  gives  the  degree  of  back -pressure  on  the  piston,  due  to  the 
exhaust  having  closed,  preventing  further  expansion. 


146  SELF-PROFELLED  VEHICLES. 

8.  It  shows  the  point  of  closing  the  exhaust. 

9.  It  shows  the   compression   of   the   residual  steam  in  the 
clearance  after  closing  the  exhaust. 

10.  It  gives  the  mean  power  used  in  driving  the  engine. 

11.  In  indicates  any  leakage  of  valves  or  piston. 

The  Indicator  Diagram  and  the  Gas  Engine  Cycle. — In  pre- 
cisely similar  fashion,  the  indicator  diagram  reveals  nine  things 
regarding  the  operative  conditions  in  the  cylinder  of  a  gas  engine : 

I.  It  gives  the  initial  pressure  from  beginning  to  end  of  the  in- 
let stroke. 


FlQ.  121. — Gas  Engine  Indicator  Card.  This  diagram  is  an  average  good  card,  show- 
ing, however,  some  slight  fluctuations  in  the  lines.  The  explosion  line  is  from 
C  to  A;  the  expansion,  from  A  to  B;  the  exhaust  at  B.  The  suction  stroke 
generally  approximates  the  atmospheric  line,  from  which  the  curve  of  compres- 
sion rises  to  C. 

2.  It  gives  the  point  of  closure  of  the  inlet  valve,  provided  the 
operation  is  irregular. 

3.  It  gives  the  curve  of  compression,  registering  the  highest 
point  of  compression  pressure. 

5.  It  gives  the  maximum  pressure  at  the  ignition  of  the  charge, 

6.  It  shows  whether  the  ignition  is  normal  or  irregular,  as 
shown  in  Fig.  133. 

7.  It  shows  the  curve  of  expansion,  indicating  whether  leak- 
age or  other  disorder  interferes  with  the  full  effective  pressure. 

8.  It  shows  the  point  of  exhaust,  enabling  .a  ready  computation 
of  the  exhaust  pressure. 

9.  It  enables  a  ready  estimate  of  the  mean  effective  pressure. 


THEOR  Y  OF  HE  A  T  ENGINES. 


147 


The  Steam  Engine  Diagram. — The  diagram  for  a  high- 
pressure  steam  cylinder  is  given  in  an  accompanying  figure.  From 
point,  A,  the  pressure  rises  from  the  compression  maximum  of 
about  50  Ibs.  to  120  Ibs.  as  the  steam  enters  the  cylinder.  The  cut- 
off occurs  in  this  cylinder  at  one-quarter  stroke,  the  expansion 
starting  at  point,  C,  and  continuing  to  the  opening  of  the  exhaust 
valve  at  point,  R.  From  this  point  to  B,  where  the  exhaust  valve 
closes,  the  returning  in-stroke  of  the  piston  drives  the  steam  out 
through  the  open  exhaust  port.  The  steam  then  remaining-  in  the 
cylinder  is  compressed  between  points,  B  and  A,  being  raised  in 
pressure  from  a  point  near  atmosphere  to  50  Ibs.  gauge. 


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FIG.  128.— Tbe  Cycle  of  a  Steam  Engine,  as  shown  by  the  Indicator  Card.  On  this 
tracing,  the  admission  id  shown  from  A  to  C;  the  cut-off  M  C ;  the  expansion 
curve  from  O  to  R ;  the  release,  or  opening  of  the  exhaust,  at  R,  exhaust  continu- 
ing from  R  to  B ;  closing  of  the  exhaust  valve  at  B ;  compression  of  the  residual 
steam  in  the  cylinder  clearance,  from  15  to  A.  The  figures  on  the  left-hand 
veitical  line  indicate  the  gauge  pressures. 

All  these  stages  are  more  graphically  illustrated  in  the  ac- 
companying diagram  of  the  cycle  of  a  steam  engine  for  the  steam 
admitted  to  one  face  of  the  piston.  In  this  figure  the  dotted  circle 
indicates  the  path  of  the  crank ;  the  arrow,  the  direction  of  rota- 
tion. The  admission  begins  a  little  before  the  completion  of  the 
stroke;  the  cut-off  is  set  somewhat  less  than  quarter-stroke;  re- 
lease, or  opening  of  the  exhaust  near  the  end  of  the  stroke ; 
closing  of  the  valve  at  the  point  marked  "compression,"  after 
which  the  steam  behind  the  piston  is  compressed  in  the  clearance 
until  the  opening  of  the  inlet  valve. 

Reading  an  Indicator  Diagram. — The  simplest  method  of 
reading  a  diagram,  so  as  to  find  the  power  exacted,  is  to  rule 


148  SELF-PROPELLED  VEHICLES. 

equidistant  lines  from  the  vertical  initial  pressure  line,  so  as  to 
divide  into  ten  equal  parts,  or  areas.  Ordinates,  indicated  by  the 
dotted  lines,  are  then  ruled  between  these,  and  given  a  value 
equivalent  to  the  average  of  pressure  represented  by  the  lines  on 
either  side,  as  indicated  by  the  point  of  contact  with  the  admission 
line  and  the  expansion  curve.  Thus  in  the  single  high-pressure 
diagram  the  first  ordinate  ruled  on  the  admission  line  has  a  value 
of  155  pounds,  which  represents  180  less  25  back  pressure. 
The  second  and  third  ordinates,  according  to  the  figures  ruled 
on  the  left-hand  vertical  line,  have  a  value  of  180  pounds;  the 
fourth,  of  165;  the  fifth,  128;  the  sixth,  98;  the  seventh,  80;  the 
eighth,  68;  the  ninth,  55;  the  tenth,  50;  showing  an  expansion  of 
over  three  volumes  from  boiler  pressure.  The  sum  of  the  press- 
ures given  is  1149,  which  divided  by  10,  the  number  of  the 
ordinates,  gives  the  average  of  all  the  pressures  acting  on  the 
piston  during  the  stroke,  or  what  is  known  as  the  mean  effective 
pressure,  at  about  115  pounds. 

In  similar  fashion  the  diagram  for  both  strokes,  inward  and 
outward,  of  the  piston  is  ruled  off  and  estimated,  the  figures  at 
the  top  of  the  figure  indicating  the  cycle  of  pressure  changes  for 
the  right-hand  stroke,  those  at  the  bottom  the  cycle  for  the  left- 
hand,  or  return,  stroke. 

Calculating  by  the  Mean  Ordinate. — A  simpler  method  for 
calculating  the  diagram  of  a  steam  or  gas  engine  is  to  find  the 
mean  ordinate  of  the  diagram  by  the  following  process:  Find 
the  centre  of  the  diagram  figure  on  the  base  line ;  erect  a  line  per- 
pendicular to  the  base  from  that  point;  draw  another  line  from 
the  base  so  that  it  touches  the  expansion  line  at  about  the  point 
of  exhaust  valve  opening,  at  such  an  angle  that  the  two  parts  on 
either  side  of  the  centre  line  will  be  equal  measuring  from  a  per- 
pendicular on  the  explosion  line  on  the  one  side,  and  from  anothei 
touching  the  "toe"  of  the  tracing  on  the  opposite  side.  The  por- 
tion of  the  centre  line  thus  laid  off  by  intersection  is  the  mean 
ordinate,  which,  multiplied  by  the  pressure  indicated  by  the  gauge 
gives  the  mean  effective  pressure  (M.  E.  P.)» 


CHAPTER    FIFTEEN. 

THE  PARTS  OP  A  GAS  ENGINE. 

Gas  Engine  Cylinder. — The  cylinder  of  a  gas  engine  is  open 
at  the  end  toward  the  crank,  and  closed  at  the  opposite  end,  save 
for  the  inlet  and  exhaust  ports,  which  are  opened  and  closed  by 
valves. 

Gas  Engine  Pistons. — The  piston  is  single-acting — which  is 
to  say,  acted  upon  by  the  power  on  one  face  only,  or  moved  by 
power  impulse  in  one  direction  only.  It  is  of  the  type  known 
as  "trunk  piston,"  consisting  of  a  cylindrical  box  of  proper  size 
to  slide  back  and  forth  in  the  cylinder  bore. 

The  portion  of  the  cylinder  length  traversed  by  the  piston  from 
end  to  end  of  the  stroke  is  called  the  sweep. 

That  portion  at  the  rear  of  the  cylinder  that  is  never  swept 
by  the  piston  is  called  the  clearance. 

The  valve  chamber  opens  into  the  clearance,  and  the  ignition 
apparatus  is  also  located  here. 

The  Clearance. — The  clearance  determines  the  degree  of  com- 
pression of  the  fuel  mixture  at  extreme  in-stroke,  when  the  piston 
has  reached  its  furthest  point  in  backward  travel. 

It  is  the  combustion  space,  or  chamber,  at  the  moment  of  ignit- 
ing the  gas. 

With  the  piston  sweep,  it  forms  the  total  cubical  content  of  the 
cylinder,  as  found  at  extreme  out-stroke,  when  the  piston  has 
reached  its  utmost  forward  point  of  travel. 

Piston  Construction  and  Proportions. — The  trunk  piston  is 
hollow,  and  within  it  is  pivoted  the  connecting  rod,  the  opposite 
end  of  which  is  pivoted  to  the  crank  pin.  Within  the  piston  the 
connecting  rod  is  pivoted  to  a  pin,  variously  called  the  piston 
pin,  wrist  pin  and  gudgeon  pin. 

The  piston  is  in  diameter  about  .002  inch  smaller  than  the 
cylinder  bore,  thus  giving  a  clearance  of  about  .001  inch  all 

149 


150 


SELF-PROPELLED    VEHICLES. 


around.  A  snug  working  fit  is  obtained  by  means  of  packing 
rings,  iron  rings  so  cut  that  the  internal  and  external  circumfer- 
ences are  eccentric,  as  shown  in  an  accompanying  figure,  for  the 
purpose  of  allowing  some  play  for  expansion,  under  the  extraor- 
dinary heat  generated  by  combustion  of  the  fuel  charge. 

Piston  Rings. — The  piston  rings  fit  into  grooves  cut  around 
the  circumference  of  the  piston,  and  are  set  in  place  by  being 
sprung  over  the  junk  rings,  or  the  portions  of  the  cylinder  cir- 


Fio.  123.— Section  through  a  typical  Trunk  Piston  for  a  Gasoline  Engine.  Around 
the  circumference,  nearthe  rear  end,  are  three  circular  grooves  for  inserting  the 
packing  rings.  Through  the  central  diameter  is  a  perforation  for  admitting  the 
piston  pin,  which  is  held  in  pi-ice  by  set  screws. 

The  proportions  of  the  piston  pi  i  must  be  carefully  calculated  for  the  load  it  is 
intended  to  bear.  In  general,  t  he  length  of  the  piston  pin  should  be  equal  to  that 
of  the  crank  pin,  and  its  diameter  such  nstobeMr  an  average  of  750  pounds  for 
each  square  inch  of  its  projected  area.  As  given  by  Roberts,  the  proper  diameter 
of  the  pin  may  be  determined  as  follows : 

Cylinder  area  X  M.  E.  P. 

Diameter  •= 

750  X  length  of  pin. 

cumference  left  after  cutting  the  grooves.  Three  or  four  rings 
are  set  around  the  piston  at  the  rear  end,  and,  in  some  engines, 
there  is  another  around  the  front  end. 

Machining  Piston  Rings. — Piston  rings  are  made  of  cast 
iron,  and  are  cut  from  a  pipe-shaped  casting.  The  casting  is 
secured  to  the  lathe  chuck,  so  that  a  cutting  tool  can  bear 
against  its  circumference  and  separate  rings  of  the  proper 
width.  Each  ring  is  then  turned  in  a  jig,  so  that  the  inner 
circumference  is  eccentric  with  the  outer,  and  a  slit  is  cut  in 
the  thinnest  section,  as  shown  in  the  figure.  Although  formed 


GAS  ENGINE  PARTS. 


151 


of  a  very  brittle  substance,  piston  rings  have  considerable  elas- 
ticity ;  being  capable  of  opening  sufficiently  to  be  slid  over 
the  junk  rings  of  the  piston,  also  allowing  of  sufficient  com- 
pression when  within  the  cylinder,  to  make  a  tight  fit. 

Poppet  Valves. — The  inlet  and  exhaust  ports  of  a  gas  engine 
of  the  four-cycle  type  are  opened  and  closed  by  poppet  or  mush- 
room valves.  These  consist  of  metal  disks,  beveled  around  one 
face,  so  as  to  fit  into  a  countersink  in  the  port  opening,  and 
carried  upon  stems  or  spindles. 


Fro.  124.— Piston  Packing  Ring  for  a  Gas  Engine  Cylinder.  The  Inner  and  ontei 
circumferences  are  eccentrically  arranged,  so  as  to  permit  of  considerable  ex- 
pansion under  heat. 

The  exhaust  valve  is  always  operated  mechanically  from  a 
cam-shaft;  the  inlet  valve  may  be  operated  similarly,  or  may  be 
opened  by  suction,  created  by  the  outward  movement  of  the 
piston. 

Automatic  and  Positive  Inlet  Valves. — The  automatic  inlet 
valve,  operated  by  suction  of  the  piston  against  the  tension  of 
a  spiral  spring,  has  been  regularly  used  on  all  gas  engines 
until  very  recently.  The  positive-operated  inlet  valve  is  now 
gaining  favor  with  designers.  The  reasons  for  this  change 


152 


SELF-PROPELLED  VEHICLES. 


are  that  the  automatic  valve  often  sticks  with  gummed  oil  on 
its  seat ;  that  the  spring  tension  may  vary,  thus  changing  the 
fuel  pressure  in  cylinder ;  that  it  is  noisy ;  that  its  operation 
on  high-speed  engines  is  unreliable.  As  against  these  defects, 
the  positive  inlet  valve  possesses  the  advantages  of  opening  and 
closing  as  desired,  without  noise  or  sticking,  and  of  giving 
precisely  the  right  pressure  in  the  cylinder,  at  both  high  and 
low  speeds. 

Valve  Springs. — Both  valves  are  held  to  their  seats  by  com- 
pression springs,  against  the  tension  of  which  they  are  opened. 


FIG.  125.— Detail  Diagram  of  the  Valves  and  Attachments  of  a  Gas  Engine  Cylinder. 
A  is  the  inlet  port  behind  inlet  valve  held  in  its  seat  by  a  tension  spring;  B,  the 
spark  pluij  lor '"jump-spark"  ignition;  C,  the  push  rod  and  compression  spring 
of  the  exhaust  valve;  D,  the  cam  opening  the  exhaust;  E,  the  exhaust  port;  F, 
the  roller  ut  end  of  valve  rod  bearing  on  the  cam,  D. 

When  the  inlet  valves  are  opened  by  piston  suction,  the  tension 
of  the  spring  is  regulated,  so  as  to  give  the  desired  initial  pres- 
sure in  the  cylinder,  as  will  be  presently  explained.  The  springs 
serve  to  hold  the  valves  securely  shut,  when  their  opening  is  not 
required. 

Elements  of  a  Vehicle  Engine. — The  essential  elements  of  a 
vehicle  engine  are: 

i.  The  carburetter,  or  vaporizer,  in  which  the  liquid  hydro- 
carbon is  transformed  into  vapor. 


GAS  ENGINE  PARTS.  153 

2.  The  cylinder,  to  which  the  gas  is  admitted  by  suction,  mixed 
with  a  suitable  suppiy  of  pure  air,  compressed  and  ignited. 

3.  An  ignition  apparatus  for  producing  the  spark  or  hot  sur- 
face essential  to  explosion. 

The  Crank  and  Driving  Gear. — In  the  disposition  of  the 
crank  and  driving  connections,  the  explosive  motor  differs 
radically  from  the  common  type  of  steam  engine.  The  piston 
rod  in  the  steam  engine  slides  through  the  stuffing  box  in  the 
cylinder  head,  and  the  crank  is  attached  to  the  forward  end  at  the 
cross  head,  which  works  between  guides.  The  gas  engine  cylin- 
der, being  open  at  the  forward  end,  has  no  head  or  stuffing  box 
and  no  piston  rod  proper;  in  fact,  the  crank  and  piston  rods  are 
combined  in  one.  The  crank  is  hung  on  the  gudgeon  pin  fixed 
midway  in  the  length  of  the  hollow  trunk  piston,  and  works  on  the 
crank-shaft  upon  which  the  fly-wheel  is  secured. 

The  fly-wheel  is  positively  essential  in  a  gas  engine  of  any 
size  or  power.  The  reason  for  this  lies  in  the  fact  that  the  ordi- 
nary four-cycle  motor,  having  but  one  power  stroke  in  every  two 
revolutions  of  the  crank  shaft,  requires  a  heavy  fly-wheel  to 
counteract  the  speed  fluctuations  and  to  "store  up"  energy  suf- 
ficient to  carry  the  rotation  through  the  three  idle  strokes  of  ex- 
haust, supply  and  compression.  For  this  reason  gas  engine  fly- 
wheels are  made  much  heavier  than  those  designed  for  steam 
engine  use.  Some  one-cylinder  gas  and  gasoline  motors  are  made 
with  two  fly-wheels,  one  on  either  side  of  the  crank  pin,  which  is, 
in  fact,  attached  midway  on  radii  of  the  two  wheels  or  "discs." 

In  several  modern  engines  the  rim  of  the  fly-wheel  is  made 
to  overhang  the  bearing,  thus,  as  is  claimed,  securing  better 
balance. 


CHAPTER  SIXTEEN. 

THE  FOUR    CYCLE   GAS   ENGINE. 

The  Cycle  of  a  Gas  Engine. — In  the  practical  operation  of  a 
gas  engine  there  are  several  parts  or  stages,  each  characterized 
by  a  particular  event.  The  cylinder  is  charged  by  an  out-stroke 
of  the  piston,  creating  a  vacuum  behind  it  and  drawing  in  the 
mixture  of  air  and  gasoline  gas  formed  in  the  carburetter.  The 
charge  is  then  compressed  by  the  return  stroke  of  the  piston, 
which  act  secures  complete  carburization  of  the  contained  air,  and 
reduces  the  mixture  to  the  proper  condition  to  be  kindled  by  the 
igniting  spark  or  other  source  of  firing.  This  causes  it  to  explode, 
or  to  expand  suddenly  and  with  great  effect,  and  drive  the  pis- 
ton outward  again.  The  fourth  stroke,  which  is  the  one  im- 
mediately following  the  explosion,  is  known  as  the  exhaust  stroke, 
from  the  fact  that  the  piston,  moving  back  again  in  the  cylinder, 
expels  the  products  of  combustion  through  the  exhaust  valve. 
This  process  completed,  the  parts  are  in  position  for  a  repeti- 
tion of  the  process,  the  valves  for  admitting  gasoline  gas  to  the 
cylinder  then  being  opened  again. 

The  Four-Cycle  Gas  Engine — These  four  strokes — two  out- 
ward and  two  inward — constitute  the  "cycle,"  and,  as  may  be 
readily  understood,  there  is  thus  only  one  power  impulse  for 
every  two  revolutions  of  the  fly-wheel.  This  power  stroke  also 
continues  while  the  crank  is  traveling  through  half  a,  revolution, 
or  through  an  arc  of  180  degrees.  It  is  also  evident  that  the 
cam  shaft,  for  operating  the  valve  system  of  the  cylinder,  re- 
volves but  once  for  every  two  revolutions  of  the  crank  shaft,  with 
which  it  is  geared.  Thus  is  secured  the  opening  of  the  charg- 
ing, or  inlet  valve,  and  of  the  scavenging,  or  exhaust,  at  pre- 
cisely the  proper  points  in  the  cycle.  The  operation  of  a  four- 
cycle gas  engine  may  be  understood  in  figs.  p.  155.  Supposing 
we  have  a  four-cylinder  motor,  the  cranks  of  whose  four  pistons 

164 


THE,  FOUR  CYCLE  ENGINE. 


155 


lll 


156  SELF-PROPELLED  VEHICLES. 

are  so  fixed  that,  counting  from  i  to  4,  we  have  pistons,  cams  and 
valves  in  positions  representing  the  four  cycles.  That  is  to  say, 
the  induction,  or  supply  stroke  would  be  occurring  in  the  first 
cylinder,  the  compression  stroke  in  the  second,  the  explosion  in 
the  third,  the  exhaust  in  the  fourth.  In  such  an  engine  the  crank 
is  turned  by  a  steady  impulse,  since  a  new  explosion  would  oc- 
cur in  each  180  degrees  of  rotation.  At  the  aspirating  or  supply 
stroke,  the  outward  movement  of  the  piston,  by  creating  a  par- 
tial vacuum,  causes  the  feed  valves  to  open  under  atmospheric 
pressure,  thus  indicating  that  the  pressure  within  is  lower  than 
that  of  the  atmosphere  without.  At  explosion  the  volume  and 
temperature  are  raised,  and  at  the  end  of  the  exhaust  stroke  the 
burned  gases  are  expelled.  The  supply  stroke  being  completed, 
and  the  feed  valves  closed  by  force  of  a  spring,  there  is  no  consid- 
erable increase  in  volume  and  pressure  due  to  contact  with  the 
hot  cylinder  walls,  nor  yet  from  the  residuum  of  burnt  products  in 
the  clearance,  although,  owing  to  the  tension  of  the  valve  spring, 
the  pressure  of  the  contained  gases  is  below  one  atmosphere.  The 
rise  in  pressure  during  the  supply  stroke  is  from  a  negative  point 
to  generally  about  13.50  pounds  to  the  square  inch.  So  soon, 
however,  as  the  compression  stroke  begins,  the  indicator  tracing 
shows  a  steady  rise  to  65  or  70  pounds  to  the  square  inch,  at  the 
completion  of  the  stroke,  according  to  the  compression  ratio,  as 
will  be  presently  explained. 

At  the  end  of  the  compression  stroke  the  gas  mixture  in  cylin- 
der has  attained  its  greatest  density,  also  its  greatest  pressure  and 
temperature  previous  to  combustion.  It  is  then  ready  for  firing, 
which  is  generally  accomplished  very  shortly  before  the  piston 
begins  the  second  out-stroke,  the  explosion  serving  to  bring  the 
gas  to  the  maximum  point  for  volume,  pressure  and  temperature 
alike.  In  fact,  the  effect,  as  shown  by  thermometer  and  indi- 
cator tests,  is  that  the  temperature  in  a  gas-engine  cylinder  rises 
during  this  stroke  from  between  500  and  700  degrees,  absolute,  as 
noted  when  the  engine  is  running  at  good  speed,  to  between  1,500 
and  2,000  degrees,  on  the  average,  and  the  pressure  from  an  indi- 
cated 6$  or  70  pounds  to  200  or  230  pounds  per  square  inch. 


THE  FOUR  CYCLE  ENGINE.  157 

The  fall  in  both  particulars  is  equally  rapid  during  the  succeeding 
in-stroke,  when  the  burnt  gases,  under  impulse  from  the  piston, 
are  expelled  through  the  open  valves. 

Regarding  the  time  of  firing  practice  differs  considerably.  Gen- 
erally, as  stated  above,  it  is  slightly  before  the  beginning  of  the 
power  stroke,  in  order  to  allow  time  for  the  burning  gas  to  begin 
expansion.  Slow-speed  motors  are  generally  fired  very  slightly 
after  the  dead  centre.  With  high-speed  motors  it  varies  from 
about  5  degrees  after  dead  centre  to  30  or  40  degrees  ahead  (as 
measured  on  the  crank).  With  a  large  spark,  hot  motor  and  well- 
mixed  fuel,  the  advanced  spark  is  seldom  set  more  than  15  or 
20  degrees  ahead. 


CHAPTER   SEVENTEEN. 
THE;  TWO   CYCLE;   GAS   ENGINE;. 

The  Two  Cycle  Engine. — To  the  present  time  the  greater 
majority  of  hydro-carbon  vehicle  engines  operate  by  the  four 
cycle  method.  There  is  another  form  of  engine,  however,  known 
as  the  two-cycle,  in  which  the  four  essential  operations,  charging, 
compression,  firing,  exhaust,  are  performed  in  one  revolution  of 
the  fly-wheel,  instead  of  two.  The  most  familiar  form  of  the 
two-cycle  engine  is  that  shown  in  the  Figures  130-131-132  and  its 
essential  features  are : 

1.  An  enclosed  crank  case  fitted  with  a  valve  arranged  to  open 
and  admit  fuel  gas  at  the  front,  instead  of  at  the  rear  of  the 
piston,  on  the  inward,  instead  of  the  outward  stroke,  as  in  the 
four  part  cycle. 

2.  Inlet  and  exhaust  parts  located  at  points  near  the  extreme 
outward  position  of  the  piston,  so  as  to  be  uncovered  during  the 
outward  stroke. 

3.  A.  by-pass  tube  connecting  the  interior  of  the  cylinder  with 
the  crank  case,  so  as  to  admit  fuel  gas  at  the  proper  point  in  the 
cycle. 

Since  all  the  essential  operations  occur  during  a  single 
revolution  of  the  fly-wheel,  every  out-stroke  of  the  piston 
is  made  under  the  stress  of  the  exploding  fuel  charge  in  the  com- 
bustion space.  The  ignited  gas  continues  expanding,  driving  the 
piston  outward,  until  the  exhaust  port  begins  opening.  Exhaust 
then  follows  rapidly  and  is  well  under  way  when  the  inlet  port, 
generally  located  on  the  opposite  side  of  the  cylinder  wall,  is  un- 
covered by  the  outward-moving  piston. 

The  fuel  gas  in  the  crank  case  is  slightly  compressed  by  the 
outgoing  piston,  and,  on  the  opening  of  the  inlet  port,  rushes 

158 


THH  TWO  CYCLE  ENGINE. 


159 


into  the  combustion  space,  being-  deflected  upward  to  the  rear  end 
of  the  cylinder  by  a  screen  or  deflector  plate  set  in  the  end  of  the 
piston.  The  inlet  of  new  fuel  gas  and  the  exhaust  of  the  burned- 
out  products  of  the  last  charge  continue  until  the  extreme  end  of 
the  stroke,  and  during  the  next  instroke,  until  the  closure,  first 
of  the  inlet,  then  of  the  exhaust  port.  From  this  point,  the  com- 
pression of  the  new  charge  begins,  and  on  the  completion  of  the 
instroke  the  charge  is  ready  for  ignition. 


FIG.  130.— Diagram  of  the  Two-part  Cycle  of  a  Gas  Engine.  I.  The  Instroke  of  tht 
piston,  showing  the  aspiration  of  fuel  gas  at  A,  into  crank  case,  B,  and  the  spark 
at  £  in  combustion  space,  D. 

Two=CycIe  Engines  for  Motor  Vehicles. — Several  recent 
makes  of  motor  vehicle  are  propelled  by  two-cycle  engines,  and, 
according  to  reports  yield  very  satisfactory  results.  The  ad- 
vantages claimed  are: 

1.  A  power  stroke  in  every  revolution  of  the  fly-wheel  for  each 
cylinder — provided  the  engine  has  more  than  one — with  twice 
the  consequent  power  effect  per  cylinder,  as  compared  with  the 
four-cycle  engine. 

2.  The  entire  absence  of  poppet  valves,  with  their  springs, 
stems,    push-rods    and    cam-shafts;    thus    effecting    a    greater 
simplicity  of  construction  and  operation. 

These  considerations  should  constitute  the  two-cycle  the  ideal 
form  of  engine  for  motor  carriage  purposes.  There  have  been, 


160 


SELF-PROPELLED  VEHICLES. 


however,  several  objections  to  its  use,  which,  so  it  is  claimed, 
have  been  only  recently  overcome.  Prominent  among  these  was 
the  fact  that  the  two-cycle  engines,  built  some  years  since,  seemed 
incapable  of  the  high  speeds  required  in  motor  vehicle  work ;  re- 
alizing at  best  not  more  than  between  300  and  400  revolutions, 
as  against  an  average  of  1,000  revolutions  for  the  four-cycle 
engine,  and  giving  only  about  60  per  cent,  of  the  power  at  the 
same  speed.  This  result  was  believed  to  follow  on  the  fact  that 
the  cylinder  would  rapidly  choke  up  with  exhaust  gas  products,_ 
which  were  unable  to  escape  when  high  speeds  were  attempted. 


FIG.  131.— Diagram  of  the  Two-part  Cycie  of  a  Gas  Engine,  II.  The  outstroke  of  the 
piston,  showing  the  exhaust  of  the  burned  out  gases  and  the  compression  of  the 
fuel  gas  in  the  crank  case. 

As  a  consequence,  the  four-cycle  engine  has  hitherto  been  con- 
sidered the  only  available  form  for  high  speed  use. 

The  two-cycle  engine  has  had  its  widest  sphere  of  use  on  motor 
boats,  but  the  highest  speed  boats  are  propelled  by  engines  of  the 
four-cycle  type.  The  majority  of  two-cycle  boat  engines,  how- 
ever, have  been  of  one  and  two-cylinder  patterns,  which  are  now 
claimed  to  be  inferior  in  speed  to  the  four-cylinder. 

Essentials  of  a  Two-Cycle  Engine. — A  successful  two-cycle 
vehicle  engine,  designed  to  operate  at  speeds  .at  all  commensurate 
with  the  four-cycle  vehicle  engines,  must  embody  precisely  one 


THE  TWO  CYCLE  ENGINE. 


161 


feature  of  design,  not  always  easy  to  realize — provision  for  rapid 
exhaust  of  the  burned  gases.  A  prominent  gas-engine  authority 
remarks:  "The  two-cycle  engine,  at  best,  is  the  next  thing  to 
an  impossibility."  By  this  statement  he  means  that,  the  act  of 
admitting  inflammable  fuel  mixture  into  the  cylinder,  already  filled 
with  flaming  gas,  without  igniting  it,  involves  something  closely 
approaching  a  contradiction  in  physical  conditions.  Were  it  not 
for  the  fact  that  the  burning  gases  actually  exhaust  faster  than 
the  new  mixture  is  admitted  under  impulse  of  their  inherent  ex- 
pansion, the  ignition  of  the  new  charge  would  seem  to  be  nean> 


.  132.—  Diagram  of  t'ie  Two-part  Cycle  of  a  Gas  Engine,  IT  I.  The  end  of  the  out- 
stroke.  The  gases  compassed  in  the  crank  ca-ie  ar*-  a-  milled  to  the  cylinder 
space,  D,  t'inmsn  the  open  iulet  port,  an<l  pa  t  th«  screen  or  deflector,  C.  Thfc 

issage  between  cy.in  ler  and  crank  case  is  controlled  by  a  butterfly  valve,  whicfc 

^re,  as  in  the  other  cuts,  is  showa  open. 


p 
n 


inevitable.  By  deflecting  the  incoming  mixture  to  the  rear  end 
of  the  cylinder,  it  follows  the  rapidly  expanding  exhaust,  coming 
into  contact  with  it  only  when  the  expansion  has  so  far  reduced 
the  temperature  that  the  danger  of  pre-ignition  is  averted.  It 
may  be  readily  seen,  however,  that  the  danger  of  such  interfer- 
ence, or,  at  best,  of  a  contamination  of  the  new  charge  to  a  point 
rendering  it  unignitable  must  result,  if  the  speed  be  increased 
beyond  a  certain  moderate  rate. 

The  Exhaust  of  a  Two=CycIe  Engine. — Many  authorities  en- 
large upon  the  danger  of  exhaust  gases  rushing  back  from  the 


162  SELF  PROPELLED   VEHICLES. 

muffler  into  the  cylinder  of  a  two-cycle  engine  and  producing  the 
condition  known  as  "choking-up''  If,  therefore,  high  speeds 
are  to  be  attempted,  the  back-pressure  of  the  muffler  must  be  re- 
duced as  far  as  possible,  and  the  exhaust  must  be  rendered  cor- 
respondingly rapid.  These  results  have  been  variously  achieved, 
familiarly : 

i.  By  making  the  exhaust  ports  twice  the  width  of  the  inlets, 
so  as  to  allow  the  burned  gases  free  egress  to  the  muffler  at  a 
much  higher  speed  than  is  achieved  by  the  incoming  mixture. 

2..  By  arranging  a  rotary  fan  or  blower  to  hasten  the  speed  and 
volume  of  the  exhaust,  and  also  assist  in  cooling  the  cylinder 
space,  as  the  new  charge  enters. 

By  using  the  latter  device  the  speed  of  the  engine  could  be  very 
materially  increased. 

Governing  a  Two=CycIe  Engine. — The  essential  features  in 
the  control  of  a  two-cycle  are  a  wire  gauze  screen  in  the  by-pass 
pipe,  for  the  purpose  of  preventing  back-firing,  or  crank-case  ex- 
plosions, which  would  undoubtedly  result  in  some  cases ;  a  butter- 
fly valve  in  the  by-pass,  for  the  purposes  of  throttling  the  volume 
of  the  charge,  in  order  to  reduce  the  speed.  The  mixture  may 
be  modified  by  controlling  the  percentage  of  gasoline,  as  in  other 
hydro-carbon  engines,  but  the  butterfly  valve  furnishes  the  most 
available  means  for  ordinary  control. 


CHAPTER    EIGHTEEN. 

THE   CONDITIONS   OF   COMPRESSION  AND   EXPANSION. 

Proportionate  Figures  for  Temperature  and  Pressure. — In 

the  operation  of  a  gas  engine,  the  fuel  gas  is  confined  within  the 
cylinder,  so  long  as  it  exerts  an  effect  on  power  and  speed.  If, 
then,  we  know  the  total  cylinder  content,  we  have  a  constant 
standard  of  comparison  for  calculating  the  pressure  and  tempera- 
ture of  a  given  mixture  of  gas  and  air  under  the  several  condi- 
tions of  the  cycle.  For,  although  the  contained  gas  occupies  the 
same  cubic  content  at  the  beginning  of  the  compression  stroke 
and  at  the  end  of  the  firing  stroke,  it  is  obvious  that  its  proper 
volume  is  vastly  increased  at  the  latter  moment,  as  indicated  by 
the  raised  pressure  and  temperature.  But,  following  the  prin- 
ciples laid  down  above,  we  find  that  the  figures  are  regular  and 
proportionate  as  between  the  initial  and  final  volumes,  pressures 
and  temperatures. 

Initial  and  Final  Figures. — Theoretically,  the  operations  of  a 
gas  engine  accord  with  the  general  laws  of  gas  under  the  influence 
of  heat  and  pressure.  Accordingly  we  speak  of : 

1.  The  initial  pressure,  temperature  or  volume,  which  belong 
to  a  gas  previous  to  either  compression  or  expansion.     In  gas- 
engine  practice  initial  figures  usually  refer  to  the  conditions  ex- 
isting at  the  completion  of  the  supply  or  aspirating  stroke  of  the 
cycle. 

2.  The  final  pressure,  temperature  or  volume,  which  belong 
to  a  gas  after  either  compression  or  expansion.    If  we  are  speak- 
ing from  the  standpoint  of  expansion  the  initial  figures  refer  to 
the  conditions  of  explosion  ;  if,  on  compression,  the  initial  figures 
refer  to  the  supply  stroke.     In  both  cases  the  final  figures  refer 
to  the  changed  conditions  found  at  the  end  of  the  operation. 

The  compression  and  explosion  figures  depend  upon  the  con- 
ditions existing  at  the  end  of  the  compression  stroke  and  at  the 
beginning  of  the  firing  stroke,  respectively. 

163 


164  SELF-PROPELLED  VEHICLES. 

Ratios  of  Figures.  —  Furthermore,  all  these  elements  are  re- 
lated according  to  the  following  principles  : 

1.  The  final  volume  divided  "by  the  initial  volume  is  equal  to 
the  final  pressure  divided  by  the  initial  pressure. 

2.  The  final  volume  divided  by  the  initial  pressure  is  equal  to 
the  initial  volume  divided  by  the  final  pressure. 

3.  The  final  volume  equals  the  quotient  found  by  dividing  the 
product  of  the  initial  pressure  and  initial  volume  by  the  final 
pressure. 

4.  The  final  pressure  equals  the  quotient  found  by  dividing  the 
product  of  the  initial  pressure  and  initial  volume  by  the  final 
volume. 

5.  The  final  pressure  also  equals  the  quotient  found  by  dividing 
the  product  of  the  initial  pressure  and  final  temperature  by  the 
initial  temperature. 

6.  The  final  temperature  equals  the  quotient  found  by  dividing 
the  product  of  the  initial  temperature  and  final  pressure  by  the 
initial  pressure. 

In  the  following  formulae, 
Let  P'  be  the  initial  pressure. 
Let  P"  be  the  final  pressure. 
Let  T'  be  the  initial  temperature. 
Let  T"  be  the  final  temperature. 
Let  V  be  the  initial  volume. 
Let  V"  be  the  final  volume. 

Then,  expressing  these  laws  mathematically,  we  have: 
P'  V  P'    V" 

\T"  .  13"   . 

P"  y  r   « 

T'P" 


rjy 


*       >  '  J-     • 


As  previously  suggested,  definite  figures  for  all  these  elements 
may  be  found  only  when  the  cubic  content  of  the  cylinder  is 
known.  The  cubic  content  of  the  stroke  and  clearance  areas  may, 


COMPRESSION  AND  EXPANSION.  165 

of  course,  be  calculated,  when  the  inside  diameter  and  length  of 
the  cylinder  and  length  of  the  stroke  are  known.  A  more  practical 
method  suggested  by  Roberts  is  to  turn  the  crank  to  the  backward 
dead  centre,  close  the  valves,  and  fill  the  cylinder  with  water.  By 
altering  the  position  of  the  crank  from  in-stroke  end  to  out-stroke 
end,  the  cubic  content  of  both  clearance  and  total  cylinder,  in- 
cluding stroke  sweep,  may  be  accurately  estimated.  The  water 
having  been  weighed  before  pouring  it  into  the  cylinder,  the 
weight  of  that  left  over  is  a  ready  indication  of  the  weight  of  that 
within. 

This  latter  method  is  particularly  convenient  where  the  cylinder 
has  a  spherical  or  enlarged  combustion  chamber,  which  would 
involve  mathematical  processes  of  considerable  intricacy  to  es- 
timate its  content  in  cubic  feet. 

At  39.1°  Fahrenheit,  water  weighs  62.5  pounds  per  cubic 
foot.  When  the  water  is  at  a  higher  temperature,  its  weight  per 
cubic  foot  may  be  found  by  the  following  formula,  in  which  T  is 
the  temperature  shown  by  thermometer ;  461,  the  constant  of  abso- 
lute temperature,  and  500,  the  absolute  temperature  of  water  at 
39.1  degrees. 

62.5  X  2 

T  +  461  500          =    Weight  per  cubic  foot. 

500         h  T   +  461 

Here  we  need  only  substitute  the  ascertained  temperature 
figures  for  T  wherever  it  occurs,  reduce  the  fractions  to  a  common 
denominator,  and  perform  the  indicated  additions  and  divisions. 

Measuring  the  Conditions  of  Operation. — The  factors  enter- 
ing to  vary  the  figures,  with  the  same  initial  pressures  in  different 
engines,  are  the  ratio  of  compression  and  the  percentage  of  the 
clearance  volume,  as  compared  with  the  total  cylinder  volume. 

The  Ratio  of  Compression. — The  ratio  of  compression  is 
found  to  be  equal  to  the  quotient  of  the  total  volume  of  the 
cylinder  from  the  beginning  to  the  end  of  the  stroke,  including 
also  the  clearance,  divided  by  the  volume  of  the  clearance,  which, 
#s  is  evident,  is  never  decreased  during  any  portion  of  a  stroke. 


166  SELF-PROPELLED  VEHICLES. 

Applying  the  rule  for  calculating  the  compression  ratios  of  two 
cylinders,  in  which  the  clearance  and  total  content  are  in  propor- 
tion of  2  to  4  and  i  to  4,  respectively,  we  derive  the  following  ex- 
pressions: 

2  +  4  3  1 +4 

2  1 

The  Percentage  of  Clearance. — The  percentage  of  the  clear- 
ance volume  is  similarly  found  by  dividing  the  volume  of  the 
clearance  by  the  volume  of  the  piston  displacement. 

In  other  words,  it  is  the  quotient  of  the  cubic  content  of  the 
clearance  (from  the  rear  of  the  cylinder  to  the  rearmost  reach  of 
the  piston  at  the  end  of  an  in-stroke),  divided  by  the  cubic  content 
of  that  portion  of  the  cylinder  included  between  the  inmost  point 
of  the  in-stroke  and  the  outmost  point  of  the  out-stroke,  as  in- 
dicated by  the  position  of  the  rear  end  of  the  piston  at  those  two 
points. 

Taking  the  same  two  cylinders,  having,  respectively,  clearances 
of  2.  cubic  feet  and  i  cubic  foot,  and  stroke-sweeps  of  4  cubic  feet, 
both,  we  find  the  clearance  percentage,  as  follows : 

-~   =  .5  or  50#.  ~  =  .-J5  or  25£. 

The  Compression  Pressure. — In  order  to  find  the  pressure  per 
square  inch  at  the  end  of  the  compression  stroke,  it  is  necessary 
only  to  multiply  the  figure  corresponding  to  an  engine  with  the 
given  compression  ratio  and  percentage  of  clearance  by  the  ascer- 
tained gauge  pressure  at  the  beginning  of  the  stroke,  or  any  other 
required  pressure  at  the  same  point.  Thus  the  initial  pressure 
at  theoretical  unity  for  a  cylinder  having  a  compression  ratio  of  3 
and  a  clearance  percentage  of  50  is  4.407,  which,  multiplied  by  13, 
the  gauge  or  desired  pressure,  gives  57.29;  by  13.2,  gives  58.17; 
by  I3>5>  gives  59-49  J  by  r4>  gives  61.69;  by  14.7,  gives  64.78. 

The  Compression  Temperature. — The  compression  tempera- 
ture is  similarly  determined  by  multiplying  the  found  or  required 
absolute  temperature  at  the  be^ii  ning  of  the  stroke  by  the  figure 
for  one  degree  for  a  type  of  engine  having  the  same  compression 
ratio  as  the  one  in  question.  Thus,  for  an  engine  having  the  ratio 


COMPRESSION  AND  EXPANSION. 


167 


Tatdefor  Calculating  the  Compression  Pressure  and  Temperature  of  a  Gas  Engine. 
A  B  C  D  E  F  O 


3. 

.4771213 

50. 

4.407 

4.264 

146.89 

142.13 

3  05 

.4842958 

48.78 

4.506 

4.358 

147.74 

142.88 

3.1 

.4913617 

47.62 

4.606 

4.452 

148.58 

143.62 

3.15 

.4983106 

46.51 

4.707 

4.547 

149.42 

144.36 

3.2 

.50515 

45.45 

4.808 

4.643 

150.25 

145.10 

3.25 

.5118834 

44.44 

4.910 

4.739 

151.06 

145.82 

3.3 

.5185139 

43.48 

6.011 

4.835 

151.87 

146.53 

3.35 

.5250448 

42.55 

5.115 

4.932 

152.67 

147.23 

3.4 

.5314789 

41.66 

5.217 

5.030 

153.47 

147.93 

3.45 

.5378191 

40.82 

5.322 

5.128 

154.25 

148.63 

3.5 

.544068 

40. 

5.426 

5.226 

155.03 

149.32 

3.55 

.5502284 

39.22 

5.531 

5.325 

155.80 

150. 

3.G 

.5563025 

38.46 

5.637 

5.424 

156.57 

150.66 

3.65 

.5622929 

37.74 

5.742 

5.524 

157.32 

151.33 

3.7 

.5682017 

37.04 

5.848 

5  624 

158.08 

151.99 

3.75 

.57-10313 

36.36 

5.956 

5.724 

158.82 

152.65 

3.8 

.5797836 

35.71 

6.064 

5.825 

159.56 

153.30 

3.85 

.5854607 

35.09 

6.171 

5.927 

160.29 

153.94 

3.9 

.5910646 

34.48 

6.280 

6.029 

161.02 

154.57 

3.95 

.5965971 

33.9 

6.389 

6.131 

161.73 

155.21 

4. 

.60206 

33.33 

6.498 

6.233 

162.45 

155.83 

4.1 

.6127839 

32.26 

6.71S 

6.440 

163.86 

157.07 

4.2 

.6232493 

31.25 

6.940 

G.G48 

165.25 

158.28 

4.3 

.6334685 

30.3 

7.164 

6.858 

166.62 

159.48 

4.4 

.6434527 

29.41 

7.390 

7.069 

167.96 

160.66 

4.5 

.6532125 

28.57 

7.618 

7.282 

169.29 

161.82 

4.G 

.6627578 

27.77 

7.847 

7.496 

170.59 

162.96 

4.7 

.6720979 

27.03 

8.07S 

7.712 

171.88 

164.09 

4.8 

.6812412 

26.32 

8.311 

7.929 

173.15 

165.20 

4.9 

.6901961 

25.64 

8.546 

8.148 

174.41 

166.29 

5. 

.69897 

25. 

8.783 

8.368 

175.64 

167.37 

5.1 

.7075702 

24.39 

9.020 

8.590 

176.87 

168.43 

5.2 

.7160033 

23.81 

9.260 

8.813 

178.07 

169.48 

5.3 

.7242759 

23.25 

9.501 

9.037 

179.26 

170.52 

5.4 

.7323938 

22.73 

9.744 

9.263 

180.44 

171.54 

5.5 

.7403627 

22.22 

9.938 

9.490 

181/60 

172.55 

5.6 

.748188 

21.74 

10.234 

9.719 

182.75 

173.55 

5.8 

.763428 

20.83 

10.73 

10.180 

185.01 

175.50 

6. 

.7781513 

20- 

11.233 

10.646 

187.22 

177.42 

Column  A  gives  the  compression  ratio  of  the  cylinder;  column  B  the  logarithm  of  the 
compression  ratio;  column  C  the  per  cent,  of  clearance  corresponding  to  any  given 
compression  ratio. 

Column  D  gives  the  figures  for  the  compression  pressure  corresponding  to  a  theoretical 
one-pound  initial  pressure.  The  figures  in  this  column,  correspond  ing  to  any  given  com- 
pression ratio,  if  multiplied  by  the  initial  pressure  in  that  cylinder  (1-1.7  minus  resistant 
strength  of  inlet  valve  spring),  will  give  the  proper  compression  pressure  correspond- 
ing to  the  initial  pressure  for  that  cylinder. 

Similarly,  column  E  gives  the  compression  pressure  corresponding  to  a  theoretical  one- 
pound  initial  pressure  for  a  scavenging  cylinder,  whose  proper  compression  pressure 
may  be  found  by  multiplying  by  the  initial  pressure. 

Columns  Fand  G  give  the  compression  temperature  for  a  plain  and  a  scavenging  cylinder, 
respectively,  corresponding  to  a  theoretical  100-degree  absolute  initial  temperature. 
The  proper  compression  temperature  for  a  cylinder  of  given  per  cent,  clearance  and 
compression  ratio  may  be  found  by  multiplying  the  figures  in  either  of  these  columns 
by  x*o  of  the  ascertained  absolute'compression  temperature  in  the  plain  or  the  scav- 
enging cylinder  in  question.  Table  from  Power. 


168  SELF-PROPELLED   VEHICLES. 

of  3,  the  theoretical  initial  temperature  is  estimated  as  1.46°, 
which,  for  an  initial  absolute  temperature  of  525°  (64°  -f-  461) 
gives  766°  (305° +461),  and  for  560°  (99°  +461)  gives 
822°  (361  "+461 ). 

High  Compression  and  Efficiency. — Other  things  being  equal, 
it  might  seem  reasonable  to  assert  that,  the  higher  the  pressure  of 
compression,  the  greater  the  rise  in  temperature  at  the  point  of 
ignition,  and,  consequently,  the  greater  the  power  efficiency  of  the 
engine.  In  accordance  with  this  view,  we  find  that,  while  in  many 
early  gas  engines  the  compression  pressure  was  very  much  below 
50  pounds  to  the  square  inch,  with  the  more  modern  and  im- 
proved patterns  it  strikes  an  average  in  the  neighborhood  of  70 
pounds. 

It  must  not  be  forgotten,  however,  that  this  rule  has  very 
definite  limitations,  and  that  beyond  a  certain  point  of  increased 
compression  pressure  the  efficiency  ratio  begins  to  decrease 
rapidly.  This  is  true,  because,  although  a  gas  is  generally  more 
explosive  under  pressure,  there  is  always  a  point  at  which  the 
rule  begins  to  change.  Again,  the  practical  reason,  that,  to  pro- 
duce a  higher  compression,  a  greater  amount  of  power  must  be 
absorbed,  renders  the  limitations  still  more  obvious. 

High  Compression  Figures. — Taking  a  theoretical  one-pound 
pressure  and  one-degree  temperature  initial,  we  have  the  follow- 
ing figures  for  varying  compression  ratios  in  non-scavenging  en- 
gines, derived  as  above : 

With  a  ratio  of  3,  we  have  4.407  for  pressure  and  1.4689  for 
temperature;  with  4,  we  have  6.498  and  1.6245,  respectively;  with 
5,  we  have  8.783  and  1.7564;  with  6,  in  the  same  way,  11.233  anc* 
1.8722.  These  figures,  multiplied  by  the  ascertained  initial  pres- 
sure and  temperature  in  any  particular  engine  of  the  same  ratio, 
will  give  the  proper  figures  for  that  engine. 

Data  on  Compression  Pressure. — On  the  matter  of  com- 
pression figures  this  quotation  from  Hiscox  will  suffice : 

"It  has  been  shown  that  an  ideal  efficiency  of  33  per  cent,  tor  38 
pounds  compression  will  increase  tQ  40  per  cent,  fpr  66  pounds,  and  43 


COMPRESSION  AND  EXPANSION.  169 

per  cent,  for  88  pounds  compression.  On  the  other  hand,  greater  com- 
pression means  greater  explosive  pressure  and  greater  strain  on  the 
engine  structure,  which  in  future  practice  will  probably  retain  the  eom- 
pression  between  the  limits  of  40  and  60  pounds. 

"In  experiments  made  by  Dugald  Clerk  with  a  combustion  chamber 
equal  to  0.6  of  the  space  swept  by  the  piston,  with  a  compression  of  38 
pounds,  the  consumption  of  gas  was  24  cubic  feet  per  indicated  horse- 
power per  hour.  With  0.4  compression  space  and  61  pounds  compression, 
the  consumption  of  gas  was  20  cubic  feet  per  indicated  horse-power  per 
hour;  and  with  0.34  compression  space  and  87  pounds  compression,  the 
consumption  of  gas  fell  to  14.8  cubic  feet  per  indicated  horse-power  per 
hour — the  actual  efficiencies  being  respectively  17.21  and  25  per  cent.  This 
was  with  a  Crossley  four-cycle  engine." 


CHAPTER    NINETEEN. 

OPERATION  AND  EFFICIENCY  IN  A  GAS  ENGINE. 

Definition  of  Efficiency. — The  efficiency  of  a  gas  engine  is 
the  "ratio  of  heat  turned  in  to  work,  as  compared  with  the  total 
heat  produced  by  combustion." 

The  British  Thermal  Unit. — The  comparison  of  heat  and 
work  in  this  particular  is  based  upon  the  amount,  rather  than 
upon  the  degree,  of  heat  used.  The  standard  is  the  so-called 
British  Thermal  Unit,  which  may  be  defined  as  the  amount  of  heat 
capable  of  raising  one  pound  of  water  through  one  degree  Fahren- 
heit. This  is  not  a  mere  question  of  thermometric  temperature. 
An  alcohol  lamp  and  a  locomotive  furnace  may  register  the  same 
degree  on  the  scale,  but  the  lamp  would  require  a  longer  period 
to  accomplish  the  above  result — in  other  words,  to  generate  one 
thermal  unit. 

The  Efficiency  Ratio. — Since  all  the  heat  generated  by  com- 
bustion of  the  gas  in  cylinder  can  positively  not  be  utilized  as 
mechanical  energy,  the  efficiency  of  a  gas  engine  is  expressed  as 
a  ratio  or  a  fraction.  Thus,  an  engine  giving  an  efficiency  of  20 
out  of  each  100  heat  units  generated  would  have  an  efficiency  of 
ao-iooths,  or  20  per  cent. 

The  Mechanical  Efficiency. — The  mechanical  efficiency  of  a 
heat  engine  must  necessarily  be  far  below  the  actual  heat  gen- 
erated, even  with  the  most  perfect  machinery  imaginable,  since 
it  seems  practically  impossible  to  fully  realize  theoretical  con- 
ditions. Thus,  in  the  operation  of  a  heat  engine,  there  must  nec- 
essarily be  some  loss  or  gain  of  heat  as  the  gas  expands.  This, 
of  course,  modifies  the  curve  of  expansion,  and  involves  a 
lower  mean  pressure  than  is  theoretically  demanded,  should 
at  any  time  be  available  for  power  effort.  No  expansion  in  a 

170 


OPERATION  AND  EFFICIENCY.  171 

practical  heat  engine  is  perfectly  adiabatic;  involving  that  the 
mean  working  pressure  is  always  below  that  required  by  theory. 

The  Conditions  of  Efficiency. — The  efficient  power  of  a  gas 
engine  is  not  dependent  wholly,  or  even  largely,  on  relative 
proportions  among  the  working  parts,  and,  at  most,  the  figures 
given  above  are  averages  for  the  best  obtainable  conditions.  These 
conditions  are  found  to  consist  principally: 

1.  In  the  use  of  the  best  qualities  of  fuel. 

2.  In  the  production  of  the  best  proportions  of  mixture  in  fuels. 

3.  In  conditions  and  means,  favorable  to  rapid  and  complete 
ignition  of  the  charge. 

4.  In  efficient  means  for  cooling  the  cylinder. 

Conditions  of  Fuel  Combustion. — In  order  to  secure  the 
proper  degree  of  power  efficiency,  it  is  important  to  consider: 

1.  Proportioning  fuel  mixture,  since  too  much  or  too  little  of 
either  air  or  hydrocarbon  gas  produces  the  effect  of  weak  or  im- 
perfect explosion  of  the  charge. 

2.  Provision  for  adequate  compression  of  the  charge,  in  ordet 
that,  despite  the  presence  of  the  burned  and  exhausted  gases  of 
previous   combustions,   there  may    be    uniformity    of    mixture 
throughout  the  mass  of  fuel  gas  in  cylinder.    This  is  an  important 
element  in  securing  rapid  and  effective  ignition. 

The  Theory  of  Fuel  Mixtures. — All  oils  and  spirits  may  be 
ignited  and  burned  if  heated  to  the  required  temperature,  differ- 
ing in  each  case,  provided  at  the  same  time  that  air  can  circulate 
freely  where  the  heating  takes  place.  The  air  is  required,  in  order 
to  furnish  a  sufficient  quanity  of  oxygen  for  combustion,  which, 
properly  speaking,  is  only  the  chemical  process  of  absorbing  oxy- 
gen. The  temperature  at  which  an  oil  or  spirit  gives  off  in- 
flammable vapors  is  called  the  Hash  point,  and  the  point  at  which 
it  may  be  ignited  and  burned  is  called  the  fire  point.  Without 
a  sufficient  quantity  of  air,  however,  no  liquid  will  either  flash  or 
fire,  even  if  confined  in  a  closed  vessel  heated  to  very  high  tem- 
perature. 


172  SELF-PROPELLED   VEHICLES. 

In  order  to  illustrate,  the  following  list  of  several  hydrocarbons, 
together  with  their  flash  and  fire  points,  is  quoted  from  a  well- 
known  authority: 

Flash  Point.     Fire  Point. 

Commercial  brandy 69  92 

whiskey 72  96 

gin 72  101 

Kerosene  (average  quality) 73  104 

Petroleum  (high  test) 110-120  140-160 

Proportions  of  Fuel  Mixtures. — In  the  open  air  the  only 
point  to  be  considered  is  the  temperature  for  flashing  or  firing, 
since  atmospheric  circulation  will  always  supply  the  full  amount 
of  oxygen  for  combustion.  In  a  gas-engine  cylinder,  closed 
from  the  outer  air,  it  is  necessary  to  know  how  much  air  must 
be  admitted.  The  most  efficient  proportions  of  air  and  gas, 
mixed  to  give  a  perfect  combustion  in  a  closed  cylinder,  may  be 
considered  a  matter  in  many  respects  relative  to  the  kind  of 
gas  employed — some  gases  require  more,  some  less,  for  the  best 
effects  from  combustion. 

Figures  for  Coal  Gas. — In  general,  however,  the  data  on  coal 
gas  may  be  taken  as  typical  for  most  fuels  available  in  ordinary 
gas-engine  service.  With  this  fuel  the  figures  for  good  efficiency 
range  between  6  to  i  and  n  to  i  for  air  and  gas,  respectively. 
That  is  to  say,  with  a  mixture  of  about  5  to  i  or  about  12  to  i, 
for  example,  the  effective  pressure  due  to  combustion — if  com- 
bustion is  possible  at  all — shows  a  marked  falling  off,  which  con- 
tinues thereafter  as  the  proportion  of  air  in  the  mixture  is  either 
diminished  or  increased. 

Effects  of  Varying  Mixtures. — Between  the  efficient  extremes 
it  has  been  found  that,  although  the  actual  indicated  explosion 
pressure  decreases  in  ratio  with  the  increased  percentage  of  air 
in  the  mixture,  the  efficiency  steadily  increases  until  the  point 
of  ii  to  i  is  approximated.  This  fact  is  explained  by  assuming 
that,  in  increasing  the  proportion  of  air  in  the  mixture,  the  tem- 
perature per  unit  of  gas  is  raised,  although  the  temperature  per 


OPERATION  AND  EFFICIENCY.  173 

unit  of  the  mixture  of  gas  and  air  is  lowered.  Since,  there- 
fore, the  gas  itself  is  the  sole  agent  of  efficiency — the  condition 
necessary  to  explosion  being  all  that  is  furnished  by  the  ad- 
mixture of  air — the  increase  in  the  proportion  of  air  in  the 
charge,  up  to  the  specified  limit,  increases  the  total  efficiency,  even 
though  lowering  the  pressure  of  the  explosion. 


FIG.  133.— Typical  Gas-Enstine  Indicator  Cards,  taken  under  actual  service  conditions. 
The  first  diagram  is  from  nn  engine  running  under  half  load  ;  the  second  from 
one  »t  full  load.  Both  exhibit  the  variations  in  the  expansion  curve,  usually 
attributed  to  consecutive  explosions.  These  cards  are  composites  of  three 
successive  strokes  each. 


Causes  of  Defective  Mixture. — As  already  suggested,  an  ade- 
quate degree  of  compression  is  as  essential  to  perfect  efficiency 
in  a  gas  engine,  from  the  fact  that  a  more  complete  mingling  of 
the  fuel  ingredients  is  thus  secured.  In  the  same  engine,  how- 
ever, as  shown  by  indicator  cards,  several  successive  firing  strokes 
will  show  a  marked  variation  in  the  pressure  rise  at  explosion. 
Some  authorities  refer  this  to  the  presence  of  residual  burned-out 
gases  in  the  clearance,  which  tend  to  stratify  the  fuel,  producing 
layers  of  incombustible  gas,  with  the  result  that  several  successive 
•~eak  explosions  occur  instead  of  one  full  and  complete  explosion. 


174  SELF-PROPELLED   VEHICLES. 

Advantages  of  Scavenging. — That  the  presence  of  non- 
combustible  burned  gases  in  the  cylinder  clearance  is  a  fertile 
source  of  lost  efficiency  seems  proved  by  the  superior  average 
performance  of  scavenging  engines,  in  which  these  residue  are 
largely  expelled. 

"A  mixture  of  9  to  I,  with  no  burned  gases  present,  gives  a  rise  of  about 
2»373  degrees;  the  same  mixture,  compressed  with  the  burned  gases  of  a 
previous  explosion  in  a  clearance  of  41  2-3  per  cent,  of  the  cylinder  volume 
gives  a  rise  of  only  about  1,843  degrees. 

"The  resulting  temperatures  of  explosion  in  the  two  cases  do  not  differ 
so  greatly  as  the  rise  in  temperature,  because  the  scavenging  engine  starts 
from  a  lower  initial  temperature  and  the  rise  during  compression  is  not 
so  great.  For  example,  assume  an  engine  with  3.4  compression  ratio,  run- 
ning scavenging  with  an  initial  pressure  of  13.2  pounds  and  an  initial  tem- 
perature of  580  degrees ;  and  suppose  a  similar  engine  running  plain,  with 
13.2  pounds  initial  pressure  and  600  degrees  injtial  temperature.  The 
results  are  compared  below  on  the  basis  of  a  9  to  i  mixture : 

Ordinary.  Scavenging. 

Initial  temperature  600  580 

Compression    temperature 921  858 

Rise  in  temperature  by  explosion 1,843  2,373 

Temperature  of  explosion   2,764  3,231 

"In  this  comparison  the  difference  in  the  rise  of  temperature  is  nearly 
29  per  cent,  while  the  difference  between  the  explosion  temperatures  of 
the  two  engines  is  only  scant  17  per  cent.  A  better  comparison  may  bf 
had  by  considering  the  pressures;  these  figure  out  as  follows: 

Ordinary.  Scavenging 

Initial  pressure  13.2  13.2 

Compression  pressure  68.86  66.4 

Explosion  pressure 206.65  250.0 

"Thus,  the  scavenging  engine  shows  a  maximum  temperature  about  17 
per  cent,  higher  than  the  other  engine,  while  its  maximum  pressure  is  r 
trifle  over  21  per  cent,  greater.  *****  While  excessive  explosion 
pressures  are  not  desirable,  it  is  clearly  advantageous,  within  practical 
limits,  to  increase  the  difference  between  the  maximum  forward  pressure 
and  that  of  compression,  because  it  increases  the  area  of  the  indicator 
diagram.  And  as  this  result  is  obtained  by  scavenging,  without  consuming 
any  more  gas,  the  superiority  of  a  scavenging  engine  is  obvious." 


CHAPTER    TWENTY. 

THE   EXHAUST   OF   A   GAS   ENGINE. 

Losses  in  the  Exhaust. — In  the  operation  of  a  gas  or  gasoline 
engine  a  large  amount  of  heat  and  power  units  are  inevitably  lost 
in  the  exhaust. 

The  principal  reason  why  this  loss  may  not  be  avoided  is  that 
the  gas,  after  explosion,  may  not  be  expanded  to  atmospheric 
pressure  within  the  cylinder.  At  the  completion  of  the  power 
stroke  the  expansion  line  stands  generally  about  or  above  the 
figure  indicated  for  compression  pressure.  It  is  necessary,  there- 
fore, to  open  the  exhaust  before  the  completion  of  the  stroke, 
generally  at  about  £  stroke.  Were  the  engine  otherwise  geared, 
and  the  piston  allowed  to  receive  the  pressure  of  the  expanding 
gas  through  its  full  stroke,  the  gas  would  not  exhaust  fast  enough 
to  avoid  buffing  the  piston  on  its  return  sweep,  since  through  an 
appreciable  distance  the  continued  expansion  would  balance  the 
rate  of  escape  through  the  exhaust  valve.  The  effect  of  this 
would  be  to  check  the  speed  and  power  of  the  engine,  with  the  re- 
sult of  absorbing  about  as  much  power  as  would  on  the  other  plan 
be  turned  to  waste. 

The  Variation  of  the  Curve  of  Expansion. — The  expansion 
following  explosion  is  not  instantaneous,  but  continues  through- 
out the  stroke,  thus  constantly  keeping  up  the  temperature  and 
pressure,  which  would,  otherwise,  tend  to  fall  regularly  from 
maximum  to  atmosphere.  Thus  the  expansion  line  on  the  indica- 
tor diagram  does  not  meet  the  compression  line  at  the  end  point 
of  the  stroke,  as  should  be  the  case  under  theoretically  perfect 
conditions.  Consequently  the  exhaust  valve  must  be  opened  be- 
fore the  completion  of  the  stroke,  as  above  stated. 

The  Ratio  of  Expansion. — As  may  be  readily  understood, 
the  practice  of  opening  the  exhaust  valve  at  about  £  power  stroke 

175 


176  SELF-PROPELLED   VEHICLES. 

involves  that  the  expansion  ratio  differs  greatly  from  the  com- 
pression ratio,  with  which,  theoretically,  it  should  be  identical. 
The  expansion  ratio  represents  the  quotient  found  by  dividing 
the  sum  of  the  total  cylinder  content  (clearance  +  piston  sweep) 
and  that  portion  of  the  stroke  and  clearance  content  left  behind 
the  piston  at  the  moment  the  exhaust  opens,  by  the  cubic  content 
of  the  clearance.  This  may  be  expressed  by  the  following 
formula : 

,,          C  -1 — ^-  _     Volume  of  Expansion 
3  Volume  of  Clearance, 

in  which  Er  is  the  ratio  of  expansion. 

C  "  the  total  cylinder  content. 

B  "  the  combustion  chamber  or  clearance  content. 

n  "  the  numerator  expressing  the  portion  of  the  cylin- 
der content  left  behind  the  piston  at  the  opening  of  the  exhaust, 
which,  as  already  stated,  is  generally  £  stroke  length,  or  £  sweep 
content  in  cubic  measure. 

Figures  for  Exhaust  Losses. — The  pressures  and  tempera- 
tures voided  in  the  exhaust  are  in  proportion,  first  place,  to  the 
figures  realized  in  explosion,  and,  secondly,  to  the  expansion  ratio 
of  the  particular  cylinder  under  test.  Both  are  found  to  decrease 
with  increasing  ratios.  Thus,  under  ordinary  conditions,  with  en- 
gines driven  by  illuminating  gas,  an  explosion  temperature  of 
3,000  and  an  explosion  pressure  of  250  for  a  ratio  of  3  give  an  ex- 
haust temperature  of  2,158  and  an  exhaust  pressure  of  59.9;  for 
a  ratio  of  3.5  they  give  2,060  and  49.0;  for  a  ratio  of  4  they  give 
1,979  ancl  41-2)  f°r  a  rati°  °f  5  tnev  give  1,851  and  30.8;  for 
a  ratio  of  6  they  give  1,752  and  24.3. 

Suppose  we  assume  an  expansion  ratio  of  5.8  in  order  to  get 
a  great  expansion,  and  a  compression  ratio  of  6.  Then  assume 
an  ordinary  engine,  because  the  effect  of  explosion  is  not  so  great 
and  a  mixture  of  12  volumes  of  air  to  i  of  gas,  because  that  is 
the  weakest  reliable  mixture.  Starting  with  the  highest  practi- 
cal initial  temperature,  660  degrees,  and  the  lowest  practical  initial 
pressure,  13,  the  following  results  are  obtained: 


THE  EXHAUST  OF  A  GAS  ENGINE. 


177 


Pressure.  Temperature. 

Initial 13  660 

Compression 146  1,236 

Rise   207  1,755 

Explosion 353  2,991 

Exhaust 35.9  1,765 

The  Muffler  or  Silencer. — The  exhaust  from  the  cylinder, 
being  commonly  expelled  at  a  pressure  between  two  and  three 
times  an  atmosphere,  would  naturally  make  considerable  noise  and 
raise  dust,  were  it  not  for  the  use  of  an  apparatus  called  the 
muffler,  or  silencer.  Although  constructed  on  various  designs, 
the  muffler  always  involves  the  same  theory  of  "breaking  up" 


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Fro.  134.— The  Benz  Exhaust  Muffler.  The  arrows  indicate  the  course  of  the  ex- 
panding exhaust  products.  Entering  at  the  left,  they  pass  through  the  per- 
forations  in  the  tube;  thence  through  the  smaller  tube  in  the  larger  chamber ; 
again  through  the  perforations  in  the  right-hand  section  of  the  tube,  and  to 
atmosphere.  The  breaking-up  of  the  gas  in  expansion  silences  the  noise  of  its 
exhaust  to  atmosphere. 

the  exhaust  gas  by  causing  it  to  pass  through  fine  perforations 
in  the  exhaust  tube,  and  of  allowing  it  to  expand  to  nearly  atmos- 
pheric pressure  in  one  or  several  successive  chambers.  Several- 
efficient  types  of  muffler  are  shown  in  accompanying  diagrams. 

Cubic  Content  of  a  Muffler. — As  indicated  by  Roberts,  the 
formula  for  the  cubic  content  of  a  muffler  best  calculated  to  save 
power  gives  3.5  times  the  square  of  the  cylinder  diameter  in 
inches  multiplied  by  the  length  of  the  piston  stroke  in  inches,  or 

M   =   3.5   D'L. 

If,  therefore,  a  cylinder  have  a  diameter  of  4^  inches  and  a 
stroke  of  5  inches,  we  have: 

M  =  3.5  X  (4.5)2  X  5  =  3.5  X  20.25  X  5  =354.375    cu.   in. 


178 


SELF-PROPELLED  VEHICLES. 


If  two  cylinders  of  this  size  exhaust  into  the  same  muffler, 
the  cubic  content  should  be  increased  by  50  per  cent. ;  if  three  cyl- 
inders, by  150  per  cent.;  if  four  cylinders,  by  200  per  cent.  In 
other  words,  under  these  several  conditions,  the  muffler  should 
be  increased  by  one-half,  once  and  one-half  and  twice  the  proper 
content  for  a  single  cylinder. 

Losses  in  the  Muffler. — Since,  as  stated,  the  principle  of  a 
muffler  involves  imposing  obstacles,  in  the  shape  of  minute  per- 
forations, etc.,  to  the  free  expansion  of  exhaust  gases,  it  furnishes 
a  large  and  undesirable  back-pressure. 


n  —  _4 

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Ito.  135.— The  "Lqomls"  Muffler.  The  exhaust  enters  the  central  tube  at  the  right- 
hand  end,  passing  out  through  slits  shown  in  its  side  to  the  main  chamber,  where 
it  is  passed  through  a  number  of  lengths  of  tubing.  Leaving  these  it  emerges  to 
atmosphere  through  another  set  of  tube  lengths. 

A  French  authority  states  that  an  engine  of  8  I.  H.  P.,  run- 
ning without  muffler,  gave  6.1  B.  H.  P.  at  967  revolutions  per 
minute,  but  with  muffler  gave  the  same  efficiency  only  on  1,012 
revolutions.  He  also  found  for  a  2.25  I.  H.  P.  engine  an  efficient 
output  of  2.16  at  2,015  revolutions  without  muffler,  and  of  1.91, 
at  2,057  revolutions  with  muffler,  claiming  a  loss  of  20  kilogram- 
meters,  or  145  foot  pounds  per  second. 

These  figures  are  fairly  typical  for  very  many  mufflers,  and,  al- 
though possibly  reduced  by  some  of  the  more  modern  models, 
represent  fairly  well  the  kind  of  obstacles  obtruded  in  the  way  of 
the  highest  mechanical  efficiency  of  the  average  gas  engine. 


Preventing  Exhaust  Losses. — The  enormous  waste,  as  indi- 
cated by  the  figures  given  above,  which  show  that,  with  average 


THE  EXHAUST  OP  A  GAS  ENGINE. 


179 


exhaust  temperature  of  1,760°  absolute,  or  1,300°  F.,  escaping 
into  an  average  atmospheric  temperature  of  70°  F.,  (1.23  X  .26) 
319.8  heat  units,  or  (319.8  X  778)  248,804  foot-pounds,  or  over 
7.5  horse-power  per  pound  of  fuel  gas  goes  through  the  exhaust 
valves,  is  a  good  argument  for  seeking  some  device  to  utilize  at 
least  a  part  of  this  lost  energy. 

Cut-Out  Mufflers. — Although  there  have  been  many  notable 
improvements,  in  both  the  design  and  operation  of  mufflers, 
within  the  last  few  years,  the  situation  remains  substantially  the 
same  in  regard  to  the  percentage  of  power  lost  in  the  exhaust. 


Ifia.  JiJO.— Section  of  the  Atkinson  Cycle  Gas  Engine,  showing  the  varying  lengths  of 
the  strokes— from  th«  top.  exhaust,  expansion,  compression,  suction;  also,  the 
ngure-of-8  path  describfd  by  the  toggle-jointed  crank  connections,  and  the  path 
or  the  crank. 

As  already  stated,  it  is  impracticable  to  expand  the  ignited  gas 
to  atmospheric  pressure  ;  hence  at  least  16  per  cent,  of  the  total 
heat  energy  is  inevitably  lost  on  this  score.  Furthermore,  if  a 
muffler  is  to  discharge  its  function  of  "muffling,"  or  silencing, 
the  exhaust,  some  back-pressure  is  unavoidable.  Several  manu- 
facturers of  mufflers  confidently  claim  that  their  inventions  pro- 
duce "no  back-pressure  whatever."  It  would  seem  that  their 
mufflers  seldom  get  upon  high-powered,  high-speed  cars,  which 
in  racing,  and  speeding  on  tour,  are  commonly  driven  with  the 
muffler  cut  out — their  drivers  being  willing  to  endure  the  deton> 


180 


SELF-PROPELLED  VEHICLES. 


ations  of  the  exhaust,  for  the  sake  of  the  additional  power  and 
mileage  capacity.  Many  mufflers  are  equipped  with  a  special 
cut-out  attachment,  which  is  used  at  starting  to  remove  back- 
pressure as  well  as  in  speeding.  On  a  4o-horse-power  car  as 
much  as  6  horse- powers  may  be  saved  by  the  muffler  cut-out. 

A  Variable=Stroke  Engine. — An  interesting  approximation  of 
theoretical  efficiency  is  found  in  the  Atkinson  cycle  scavenging 
engine,  which  proved  able  to  expand  the  charge  from  185  pounds 


-SUCTIOM 
COMPRESSION 
LXPAHSIOK     (WOKKIHO 
EXHAUST      (fVil  STflOff 


Via.  137.— Indicator  Card  for  the  Atkinson  Variable  Stroke  Four-Part  "Two-Cycle** 

Gas  Engine. 

at  explosion  to  10  pounds  gauge,  at  the  completion  of  the  power 
stroke.  In  this  engine  the  piston  rod  is  connected  to  a  double 
toggle  joint,  as  indicated  in  the  Figure  186,  page  179,  which 
so  varied  the  length  of  the  several  strokes  of  a  four-part  cycle,  as 
to  give  a  suction  stroke  through  about  one-half  the  sweep  length, 
a  return  compression  stroke  to  a  point  about  5-6  the  sweep,  an  im- 
pulse stroke  from  that  point  clear  forward,  and  an  exhausting 
stroke  from  end  to  end  of  the  cylinder.  As  claimed  in  a  published 
description,  the  working  effects  are  that 

"The  clearance  space  beyond  the  terminal  exhaust  position  of  the 
piston  is  so  small  that,  practically,  the  products  of  combustion  are  entirely 
swept  out  of  the  cylinder  during  the  exhaust  stroke,  so  that  each  in- 
coming charge  has  the  full  explosive  strength  due  to  the  mixture  used." 

The  accompanying  indicator  card  of  an  Atkinson  engine  of 
18  I.  H.  P.,  working  at  130  revolutions  per  minute,  with  a  mean 


THE  EXHAUST  OF  A  GAS  ENGINE. 


181 


pressure  of  49  pounds,  shows  the  excellent  results  achieved  by 
thus  varying  the  length  of  the  several  strokes.  But  such  a  pro- 
cedure is  impossible  in  the  ordinary  four-cycle  engine,  which  finds 
the  only  available  method  of  securing  approximately  complete 
combustion  in  varying  proportions  of  the  fuel  mixture  and  by 
scavenging  the  cylinder. 

Although  the  complications  of  the  Atkinson  engine  proved  it 
difficult  to  handle  for  stationary  purposes,  there  can  be  no  doubt 
but  what  it  furnishes  the  elements  of  an  ideal  automobile  motor, 
as  will  doubtless  be  some  day  realized. 


PiO.  138,  —  Crossley  Three-Cylinder  Compound  Gas  Engine.  The  two  end  cylinders 
are  high  pressure ;  the  central  one,  low  pressure.  The  exhaust  from  the  two 
high-pressure  cylinders  is  admitted,  alternately,  to  the  low-pressure  cylinder  by 
the  piston  valve,  operated  by  the  crank  and  rotating  shaft  shown  at  the  left. 
The  exhaust  from  the  low-pressure  cylinder  passes  upward  through  the  port  at 
its  top. 

Compound  Gas  Engines. — Compounding  for  gas  engines  cyl- 
inders has  been  proven  an  efficient  means  for  utilizing  the  com- 
mon waste  of  the  exhaust.  The  accompanying  figure  of  the 
Crossley  &  Atkinson  compound  gas  engine  shows  three  cylinders 
— two  primary,  or  high-pressure,  between  which  is  a  secondary, 


182  SELF-PROPELLED   VEHICLES. 

or  low-pressure.  The  cubic  content  of  the  low  pressure  cylindei 
is  about  twice  that  of  either  of  the  high  pressure  cylinders,  thus 
allowing  the  exhaust  gas  to  expand  very  nearly  to  atmospheric 
pressure,  when  fed  into  it  from  either  of  the  others.  The  crank 
shaft  is  so  arranged  that,  while  the  two  low  pressure  pistons  are 
at  the  dead  end  of  the  in-stroke — the  one,  of  compression,  the 
other,  of  exhaust,  for  example — the  low  pressure  piston  is  at  the 
dead  end  of  its  out-stroke,  or  power-stroke.  Thus  the  exhaust 
gas  is  fed  to  the  low  pressure  cylinder  from  both  the  high  pressure 
cylinders  alternately,  and  performs  a  power-stroke  once  in  each 
revolution  of  the  fly-wheel,  always  alternately  to  either  of  the 
others.  As  may  be  seen  from  examination  of  the  drawing,  con- 
nection between  the  high  pressure  and  low  pressure  cylinders  is 
had  by  means  of  a  triple  piston  valve  moved  longitudinally  on  a 
secondary  shaft  and  so  arranged  that  pure  atmospheric  air  mav  be 
admitted  to  the  centre  cylinder,  when  either  of  the  others  misses 
fire. 


CHAPTER    TWENTY-ONE. 

WATER-COOLING   FOR  THE   CYLINDER. 

Water-Cooling  for  Cylinders. — By  the  far  the  greater  pro- 
portion of  gas  engines — those  employed  alike  for  general  power 
purposes  and  in  propelling  motor  vehicles — have  water-cooled 
cylinders,  the  water  for  this  purpose  being  admitted  to  a  jacket 
or  water  space  cast  around  the  cylinder's  circumference  This 
water  circulates  between  the  jacket  space  and  the  feed  tank, 
either : 

1.  By  gravity,  in  accordance  with  the  laws  of  liquids,  which 
cause  the  heated  layers  to  rise  from  the  bottom  to  the  top  of  the 
reservoir,  and  the  cooler  layers  to  fall  correspondingly. 

2.  By  forced  circulation,  under  impulse  from  a  rotary  or  cen- 
trifugal pump,  which  keeps  the  water  in  constant  motion. 

Air-Cooling  for  Cylinders. — In  recent  years  air-cooling  for 
automobile  engine  cylinders  has  been  successfully  achieved  in  a 
variety  of  ways : 

1.  By  providing  a  sufficiently  large  radiating  surface  by  means 
of  cast  flanges  or  gills,  inserted  pins  and  tubes. 

2.  By  using  unusually  large  exhaust  valves,  so  as  to  cool  the 
combustion  space  between  power  strokes. 

3.  By  combining  large  radiating  surfaces  with  low  speeds  in 
multiple-cylinder  engines. 

4.  By  the  use  of  auxiliary  exhaust  ports,  combined  with  sur- 
face radiation. 

5.  By  forced  draught  of  air  circulating  through  an  air  jacket 
around  the  cylinder. 

The  greater  majoritv  of  air-cooled  engines  have  rotary  fans  at- 
tached, for  the  purpose  of  increasing  radiation  with  air  currents 
at  high  speed. 

183 


184 


SELF-PROPELLED   VEHICLES. 


The  Theory  of  Cylinder  Cooling. — The  prime  necessity  in- 
volved in  efficient  means  for  cooling  a  gas-engine  cylinder  is  that 
the  temperature  of  the  cylinder  is  normally  maintained  below  the 
point  at  which  the  lubricating  oil  will  otherwise  carbonize. 
Furthermore,  the  walls  would  also  become  so  heated  that  the  fuel 
charge  would  be  fired  out  of  time,  with  the  result  of  disarranging 
the  cycle  and  stopping  the  engine.  Although  the  "cooling  sys- 
tem" is  a  positive  necessity  over  the  combustion  space,  for  the 
reasons  above  stated,  it  forms  a  serious  consideration  in  estimates 
on  efficiency  by  absorbing  a  large  proportion  of  the  heat  units 
generated  by  ignition  of  the  fuel,  and  thus,  under  any  conditions 
operating  to  reduce  the  total  theoretical  efficiency,  even  though 
by  a  very  small  fraction. 


FIG.  138.— Diagram  of  a  Gravity  Water-Clrcnlatlon  Pystem  for  a  Gaa-Engtae 
Cylinder.  Aa  indicated  by  the  arrows,  the  water  from  the  tank  enters  the  jacket 
of  the  cylinder  at  the  lowest  point,  and  being  there  subjected  to  the  heat  of  the 
cylinder  walls,  rises  to  the  level  of  the  tank  water :  thus  maintaining  a  continuous 
circulation. 

Jacket  Water:  Its  Rate  and  Quantity. — On  this  point  His- 
cox  makes  an  interesting  statement  on  the  proportions  of  ab- 
sorbed and  efficient  heat  units,  as  estimated  under  typical  condi- 
tions. He  says: 

"In  regard  to  the  actual  consumption  of  water  per  horse-power  and  the 
amount  of  heat  carried  off  by  it,  the  study  of  English  trials  of  an  Atkin- 
son, a  Crossley,  and  a  Griffin  engine  showed  62  pounds  of  water  per 
indicated  horse-power  per  hour,  with  a  rise  in  temperature  of  50°  F.,  or 
3,100  heat  units  carried  off  in  the  water  out  of  12,027  theoretical  heat  units 
that  were  fed  to  the  motor  through  the  19  cubic  feet  of  gas  at  633  heat 
units  per  cubic  foot  per  hour. 


WATER-COOLING  THK  CYLINDER. 

"Theoretically,  2,564  heat  units  per  hour  are  equal  to  one  horse-power. 
Then,  0.257  of  the  total  was  given  to  the  jacket  water,  0.213  to  the  indi- 
cated power,  and  the  balance,  53  per  cent.,  went  to  the  exhaust,  radiation 
and  the  reheating  of  the  previous  charge  in  the  clearance  and  in  expanding 
'.he  nitiogen  of  the  air.  *  *  * 

"In  a  trial  with  a  Crossley  engine,  42  pounds  of  water  per  horse-power 
per  hour  were  passed  through  the  cylinder  jacket,  with  a  rise  in  tempera- 
ture of  128°  F. — equal  to  5,3/6  heat  units  to  the  water  from  12,833  heat 
units  fed  to  the  engine  through  20.5  cubic  feet  of  gas  at  626  heat  units 
per  cubic  foot" 

Gas  Consumption  and  Power  Efficiency. — On  the  point  of 
gas  consumption  per  horse-power  under  varying  conditions,  His- 
cox  states: 

"An  experimental  test  of  the  performance  of  a  gas  engine  below  its 
maximum  load  has  shown  a  large  increase  in  the  consumption  of  gas 
per  actual  horse-power,  with  a  decrease  of  load,  as  the  following  figures 
from  observed  trials  show:  An  actual  12  H.  P.  engine  at  full  load  used 
15  cubic  feet  of  gas  per  horse-power  per  hour;  at  10  H.  P.,  15^2  cubic 
feet;  at  8  H.  P.,  16^2  cubic  feet;  at  6  H.  P.,  18  cubic  feet;  at  4  H.  P.,  21 
cubic  feet;  at  2  H.  P.,  30  cubic  feet  of  pas  per  actual  horse-power  per 
hour.  This  indicates  an  economy  gained  in  gauging  the  size  of  a  gas 
engine  to  the  actual  power  required,  in  consideration  of  the  fact  that  the 
engine  friction  and  gas  consumption  for  ignition  are  constants  for  all 
or  any  power  actually  given  out  by  the  engine." 

Efficiency  and  Structural  Conditions. — As  already  stated,  an 
increase  in  compression,  involving  a  smaller  combustion  chamber 
or  a  longer  stroke,  ensures  a  higher  temperature  and  explosive 
force  at  ignition.  But,  in  obtaining  these  ends  by  a  relatively 
longer  piston-sweep,  we  are  met  by  the  difficulty  of  exposing  the 
ignited  gas  to  a  commensurately  larger  area  of  heat-absorption 
through  the  circulating  jacket-water.  It  is  obvious,  therefore, 
that  economy  in  this  respect  must  be  obtained  by  some  mechanical 
or  physical  variation  in  the  conditions  of  operation. 

Heat  Economy:  High  Speeds, — For  example,  considerable 
economy  in  fuel-consumption  may  be  obtained  by  increasing  the 
speed  of  the  engine,  which,  when  the  cycle  is  well  established,  in- 
volves that  the  explosive  impulses  succeed  one  another  so  rapidly 


186 


SELF-PROPELLED  VEHICLES. 


that  the  percentage  of  heat  units  absorbed  by  the  jacket  water  i? 
constantly  reduced.  Such  a  reduction  of  power-output  involves, 
of  course,  a  lower  speed,  and  is  accomplished  by  regulating  the 
gas  and  air  supply.  But  if,  according  to  the  figures  quoted  above, 
a  12  H.  P.  engine  at  full  power  consumes  15  cubic  feet  of  gas  per 
horse-power  pei  hour,  which  is  180  cubic  feet  per  hour,  it  will 
at  10  horse-power  consume  155  cubic  feet,  or  86  per  cent.;  at  8 
horse-power,  132  cubic  feet,  or  75  per  cent.;  at  6  horse-power, 
108  cubic  feet,  or  60  per  cent. ;  at  4  horse-power,  84  cubic  feet,  or 
46  per  cent.,  and  at  2  horse-power,  60  cubic  feet,  or. 33  per  cent. 
The  waste  in  fuel  gas  under  low  speed  and  low  power  conditions 
may  thus  be  readily  understood — one-sixth  of  the  stated  horse- 
power from  one-third  of  the  full  gas  supply. 


Fm.  140. —Section  through  a  Gas  Engine  Cylinder  having  a  spherical  clearance  and  a 
spherical  depression  on  the  piston,  head.  The  shaded  sections  at  top  and  bottom. 
Indicate  the  water  jackets.  The  concavities  are  somewhat  greater  than  are  me! 
in  general  practice.  Few  builders  use  the  concaved  cylinder  head. 

Heat  Economy:  Spherical  Clearance. — A  number  of  gas  en- 
gines achieve  an  economy  in  the  use  of  heat  and  power  units  by 
having  the  piston  and  the  combustion  chamber  of  concave  profile, 
so  as  to  form  a  spherical,  spheroidal  or  elliptical  clearance  at  the 
end  of  the  in-stroke.  That  is  to  say,  the  rear  end  of  the  cylinder 
is  dome-shaped  and  unjacketed,  and  the  opposing  end  of  the 
trunk  piston  is  correspondingly  hollowed  or  concaved,  thus  pro- 
viding a-  large  uncooled  surface  at  either  end  of  the  combustion 
chamber  during  the  entire  cycle.  Indeed,  wjiile  this  arrangement, 
permits  of  a  clearance  at  the  end  of  the  in-stroke,  of  the  smallest 
possible  area  on  the  cylinder  walls,  it  provides  a  total  increas?  m 
clearance  volume  on  a  stated  wall  surface  between  20  and  40  pel 
cent,  in  engines  of  ordinary  design. 


WATER-COOLING  THE  CYLINDER.  187 

Hiscox  estimates  that,  while  the  wall  surface  of  a  cylindrical 
clearance  space  of  one-half  its  unit  diameter  in  length  contains 
3.1416  square  units  and  0.3927  cubic  unit,  the  same  surface  in 
square  unit  measure,  with  a  spherical  combustion  chamber  has  a 
volume  of  0.5236  cubic  unit,  representing  a  gain  in  volume  of 
33>3  per  cent.  (5236— 3927=1 309X3 =3927)-  Such  superior 
volume,  on  equal  wall  surface,  being  fully  available  at  the  moment 
of  explosion,  when  the  greatest  possible  degree  of  heat  and  pres- 
sure is  desirable  to  promote  expansion,  must  vastly  increase  the 
effective  power  of  the  engine. 

Heat  Economy:  Temperature  of  Water. — Another  consider- 
ation of  importance  in  calculating  for  heat  economy  in  a  gas  en- 
gine is  that  the  temperature  of  the  jacket  water  should  be  main- 
tained at  a  point  favorable  to  moderate  absorption  of  superfluous 
heat.  The  temperature  of  the  water  must  not  be  too  low — the 
cooling  must  not  be  a  freezing  process ;  since,  as  is  evident  from 
foregoing  statements,  the  efficiency  of  the  engine  will  fall  ac- 
cordingly. The  best  practice  is  to  supply  water  to  the  jacket  at 
a  temperature  of  a  few  degrees  below  the  boiling  point,  permit- 
ting it  to  be  returned  to  the  reservoir  at  a  temperature  slightly 
above. 

Heat  Economy:  Rate  of  Absorption. — A  prominent  Ameri- 
can gas  engine  authority  writes : 

''A  motor  is  hotter  when  the  water  is  boiling  rapidly  than  when  it  is 
boiling  slowly,  and  the  fact  that  more  heat  units  are  being  absorbed  by  the 
water  proves  that  the  engine  is  doing  harder  work  and  not  that  it  is  cooler 
than  before.  The  writer  favors  boiling  water  as  the  proper  temperature 
and  a  gravity  circulation  as  the  proper  circulating  method,  because  this 
method  most  nearly  insures  a  fixed  temperature  for  the  motor  to  work 
under.  If  kept  below  the  boiling  point  the  temperature  of  the  motor  will 
vary  as  the  work  varies.  If  air-cooled  it  will  vary  with  the  wind  or  the 
speed  of  the  vehicle.  If  circulated  by  the  pump  the  temperature  will  vary 
as  the  speed  of  the  pump  varies,  but  with  the  boiling  water  system  it  re- 
mains reasonably  constant  and  permits  the  finest  adjustment  of  the  mix- 
Lure  and  the  best  results  from  the  sparking." 


188 


SELF-PROPELLED   VEHICLES. 


Heat  Economy:  Rate  of  Water  Circulation. — The  plea  for 
gravity,  or  thermo-siphonic  circulation,  just  quoted,  does  not  rep- 
resent the  opinions  of  many  experts.  Thus,  an  able  writer  on 
gas  engines  in  a  leading  periodical  says : 

"The  more  rapidly  the  water  passes  through  the  jacket,  the  lower  will 
be  the  temperature  of  the  issuing  jacket  water,  but  the  heat  units  will  be 
greater,  within  the  usual  limits  of  practice.  For  example,  suppose  the 
jacket  water  passes  through  at  the  rate  of  16  pounds  a  minute  and  rises 
from  60°  F.  to  140°  F.  in  passing  through.  To  raise  16  pounds  of  water 
80  degrees  requires  1,280  B.  T.  U.  (British  thermal  units),  and  as  the 


Fro.  HI.  FIG.  142. 

FIGS.  141-142.— Two  Types  of  Circulating  Pump  for  Use  in  the  Water-Cooling  System 
of  Gas  Engines.  In  both  cases  the  water  is  raised  by  the  u-e  of  a  rotating  water- 
tight piston,  being  compelled  to  follow  the  designed  course  by  the  reduction  of 
the  space  it  can  occupy  around  the  shaft  of  the  piston. 

difference  between  the  average  temperature  within  the  cylinder  (usually 
about  1,000°  F.)  and  that  of  the  jacket  water  (in  this  case  100°)  is  900 
degrees,  there  are  1,422  heat  units  per  minute  transmitted  through  the  walls 
of  the  cylinder  per  degree  of  difference  between  inner  and  outer  average 
temperatures. 

"Now  reduce  the  rate  of  flow  of  the  jacket  water  to  9.57  pounds,  and, 
assuming  that  the  average  temperature  in  the  cylinder  remains  constant, 
the  water  will  issue  at  a  temperature  of  190°  F.  This  means  a  rise  of  130 
degrees,  and  to  heat  9.57  pounds  of  water  per  minute  130  degrees,  will 
require  9.57  X  130=1,244  heat  units  per  minute,  which  is  36  less  than 
before.  A  saving  of  36  heat  units  per  minute  means 

36  X  778 

-  =  .8487  H.  P.,  gross. 
33,ooo 

"As  a  matter  of  fact  the  flow  of  water  would  need  to  be  less  than  9^ 
pounds  a  minute  in  order  to  raise  the  temperture  to  190°  F.,  because  as 
the  jacket  water  increases  in  temperature,  the  average  temperature  in  the 


WATER-COOLING  THE  CYLINDER. 


189 


cylinder  increases,  making  the  difference  between  the  two  less  than  if  the 
internal  temperature  remained  constant.  This  decreases  the  transmission 
of  heat  units  to  the  water.  The  effect  of  varying  the  flow  of  jacket  water 
cannot  be  computed  accurately,  because  the  internal  temperature  cannot 
be  computed,  and  the  exact  heat  conductivity  of  the  cylinder  walls  is  un- 
known. But,  as  the  foregoing  rough  example  clearly  shows,  the  tem- 
perature of  the  issuing  jacket  water  should  be  kept  as  high  as  practicable 
by  adjusting  the  rate  of  flow. 

"The  limit  to  the  allowable  increase  in  jacket  water  temperature  is  set 
by  the  cylinder  oil.  The  cylinder  walls  must  not  be  allowed  to  become  so 
hot  as  to  decompose  the  oil.  r>r  the  very  obvious  reason  that  decomposed 
oil  does  not  lubricate. 


FIG.  143. — An  example  of  a  radiator  and  \vater  cooling  system  with 
pump  circulation.  The  cooling1  is  assisted  by  a  fan  geared  to  the 
engine  which  induces  a  current  of  air  through  the  radiator  when 
the  car  is  standing. 

Heat  Economy:  Regulating  Jacket= Water  Temperature. — 

If  we  play  a  hose  upon  the  surface  of  a  gas-engine  cylinder,  the 
absorption  of  heat  will  be  so  rapid  that  motion  will  cease.  Con- 
versely, the  efficiency  of  the  engine,  within  limits,  increases  with 
the  rise  in  jacket-water  temperature.  The  limits  under  ordinary 
conditions  of  operation  are  set  at  the  point  when  the  water  begins 
steaming.  It  is  necessary,  therefore,  to  provide  for  the  radiation 
of  enough  thermal  units  to  keep  the  water  from  changing  its 
form.  For  this  purpose  radiators  of  the  several  forms  known  to 
automobile  construction  are  used. 


190  SELF-PROPELLED   VEHICLES. 

Radiators  for  Cooling  Jacket  Water. — After  leaving  the 
water  jacket  of  the  engine,  the  water  is  forced  through  the  radia- 
tor, before  being  returned  to  the  tank.  Radiators  are  made  in 
two  general  styles : 

1.  Radiators  composed  of  coils  of  tubing  having  a  number  of 
metal  gills  or  fins  let  over  the  tube  circumference. 

2.  Radiators  consisting  of  a  flat  tank  pierced  with  a  multitude 
of  small  tubes — like  the  flues  of  a  boiler.     This  kind  is  the  well- 
known  Mercedes  cellular  or  "honeycomb"  radiator. 

Both  varieties  of  radiator  are  made  preferably  of  copper,  a 
metal  having  a  high  heat-conducting  capacity. 

In  both  varieties  of  radiator  the  water  is  cooled  by  air  currents 
passing  through  the  fins  or  flue-tubes,  extracting  the  heat,  in 
proportion  to  the  available  cooling  surface  exposed. 

The  Dimensions  of  Radiators. — The  following  data  are  given 
for  the  dimensions  of  radiators  of  both  varieties  : 

The  cooling  surface  of  a  tubular  radiator,  stated  in  square 
inches,  is  the  product  of  the  length  of  the  tubes  by  their  circum- 
ference, plus  the  area  of  one  fin  multiplied  by  the  total  number 
of  fins. 

The  cooling  surface  of  a  cellular  radiator,  stated  in  square 
inches,  is  the  product  of  the  circumference  of  one  cell  or  flue 
multiplied  by  its  length,  multiplied  by  the  number  of  cells  or 
flues. 

The  usually  accepted  standard  for  radiator  dimensions  requires 
5  square  feet  of  cooling  surface  per  indicated  horse-power.  This 
gives  9  feet  of  ^-inch  tube,  or  6  feet  of  ^4-inch  tube  per  indi- 
cated horse-power. 


CHAPTER    TWENTY-TWO. 


AIR-COOLING     FOR     THE     CYLINDER. 

Air  Cooling  for  Cylinders. — While,  as  a  general  proposition, 
it  may  be  said  that  the  cooling  of  a  gas-engine  cylinder  is  best 
accomplished  by  water-circulation,  a  number  of  recent  carriages 
both  light  and  heavy  have  successfully  used  air-cooling  devices. 
To  within  a  very  few  years  it  has  been  held  that  air  cooling  is 
impracticable  for  vehicle  motors,  and,  on  the  basis  of  trials  made 
by  French  builders,  the  statement  has  always  been  made  that, 
while  an  air-cooled  cylinder  will  work  very  well  on  a  light  high 
speed  vehicle  or  cycle,  it  is  impossible  for  automobiles  of  large 


•EH 


FIG.  144.— Detail  Cylinder  Head  of  the  Simms  Cycle  Engine,  showing  fan  wheel, 
cooling  ribs,  and  peculiar  arrangement  for  opening  the  exhaust. 

power,  particularly  in  climbing  hills  and  in  hot  weather.  Daim- 
ler's early  motors  were  air  cooled  by  means  of  a  rotary  fan  on  the 
crankshaft  that  created  a  forced  draught  through  an  air  jacket 
surrounding  the  cylinder,  as  is  shown  in  a  subsequent  cut.  Later 
on,  automobile  builders,  such  as  Mors,  Decauville,  Darracq,  and 
also  Panhard-Levassor,  used  motors  on  heavy  carriages  with 
the  cylinders  cooled  by  peripheral  fins  or  flanges.  The  principal 
trouble  with  these  cylinders  was  that  under  heavy  load  the  gen- 
erating of  heat  was  so  rapid  as  to  clog  the  piston,  ignite  the 

191 


192 


SELF-PROPELLED  VEHICLES. 


lubricating  oil,  or  to  produce  premature  explosion  of  the  charge. 
Largely  for  this  r^son,  the  water-cooling  system  became  univer- 
sal, except  for  very  light  vehicles  and  cycles  intended  to  be  driven 
at  high  speeds.  In  order  to  assist  the  work  of  cooling  the  cylin- 
der, several  builders  early  adopted  the  plan  of  using  rotary  fans 
to  create  a  forced  draught  against  the  fins  cast  on  the  cylinder's 
walls.  Such  a  device  greatly  increased  the  cooling  properties  of 
the  motor,  even  when  the  vehicle  was  moving  at  low  speed.  This 
was  particularly  true  with  the  Simms  fan-cooled  cylinder,  on  the 


FlG.  145.— The  Knox  Pin-Cooled  Cylinder.    In  this  engine,  pins  are  used  for  radiating 
Instead  of  the  usual  flanges  or  ribs  as  on  other  air-cooled  cylinders. 

walls  of  which  were  cast  very  deep  longitudinal  flanges.  An 
English  builder,  Turell,  constructed  a  three-wheeled  carriage 
propelled  by  a  motor  with  ribs  of  this  description.  It  was  found 
however  that,  with  a  motor  of  2.  horse-power,  and  over,  the 
draught  created  at  high  speed  was  not  sufficient  for  cooling  and 
that  the  cylinder  would  quickly  become  overheated,  with  the  re- 
sult the  exhaust  walls  would  be  loosened  and  the  head  frequently 
red  hot.  It  seems  to  have  been  reserved  for  American  inventors 
to  design  successfully  air-cooling  systems.  One  of  the  most 
noteworthy  of  this  is  the  Knox  pin-cooled  cylinder,  in  which  a 


AIR-COOLING  THE  CYLINDER. 


193 


large  number  of  brass  pins  are  screwed  into  suitable  holes  on 
the  outside  of  the  cylinder's  wall.  According  to  claims  this  de- 
vice increases  the  cooling  surface  nearly  100  per  cent.,  and  is  ex- 
ceedingly efficient  in  utilizing  the  heat  absorbing  properties  of 
air  under  draft. 

In  connection  with  the  use  of  corrugated  pins  on  the  outside 
surface  of  the  cylinder,  a  rotary  fan  is  used,  and  this,  being 


FIG.  146. — The  Cameron  Air  Cooled  Engine.  The  fan  shown  at  the  left 
induces  a  current  of  air  which  passing  over  the  large  surface  pre- 
sented by  numerous  ribs,  cools  the  cylinders.  The  valves  are  located 
above  the  cylinder  bore  in  opposite  chambers  and  work  horizontally. 
Each  valve  is  operated  by  a  long  vertical  lever  A,  pivoted  at  R.  The 
upper  end  C  bears  upon  the  end  of  the  valve  stem  and  its  lower  end 
carries  a  roller  against  which  bears  the  camshaft  cam  D.  The 
upper  end  of  the  lever  or  valve  rocker  arm  is  split  and  takes  a 
threaded  piece  E,  which  rests  upon  the  end  of  the  valve  stem.  By 
the  adjustment  of  this  the  timing  of  the  valve  is  accomplished.  The 
lower  end,  with  its  roller  is  contained  within  a  small  cubical-shaped 
expansion  on  a  detachable  plate  secured  to  the  side  of  the  crank 
case,  the  end  of  the  valve  rocker  arm  working  in  a  slot  F  in  the 
top  of  the  expansion. 

driven  direct  from  the  main  shaft  by  a  worm  gear,  always  rotates 
with  the  speed  of  the  engine,  thus  providing  a  sufficient  draft 
for  cooling  purposes  at  all  speeds.  The  problem  has  been 
differently  solved  by  other  American  inventors.  Thus  the 
builders  of  the  Crest  carriage  use  a  cylinder  with  deep 
longitudinal  flanges,  which  according  to  claims  and  re- 


194 


SELF-PROPELLED  VEHICLES. 


ported  tests  is  very  efficient  in  spite  of  the  fact  that  the  motor  is 
set  vertically  in  the  carriage.  Briefly  described,  the  flanges  are 
so  arranged  as  to  be  deepest  over  the  combustion  spaces,  thus 
giving  the  cylinder  an  approximate  pear  shape.  The  success  of 
the  air  cooling  is  due  to  the  extremely  large  radiating  surface, 
due  to  the  use  of  very  wide  vertical  radiating  vanes,  to  the  free 
passage  of  air  directly  behind  the  valve  chamber — this  space  being 


FIG.  147.— Section  through  theFritscher-Houdry  Single-cylinder  Engine,  showing  the 
supplementary  or  "anticipatory"  exhaust  valve  at  the  point  of  piston  outstroke. 
The  supplementary  exhaust  used  on  modern  engines  is  similar  to  this,  only 
mechanically  operated. 

usually  filled  with  solid  metal — and  to  the  slight  tapering  of  the 
upper  end  of  the  piston.  The  motor  is  of  the  conventional  ver- 
tical type,  excepting  that  the  inlet  and  exhaust  valves  are  larger 
in  proportion  to  bore  than  is  usually  used.  According,  to  claims, 
apparently  verified  by  independent  test,  it  can  safely  run  at  'a 
speed  of  between  1,900  and  2,000  revolutions  per  minute. 

For  air-cooling  the  cylinders  of  the  Regas  engine,  a  sheet  steel 
jacket  carrying  numerous  copper  tubes,  each  having  a  longitud- 


AIR-COOLING  THE  CYLINDER.  195 

inal  slot  at  its  base,  is  slid  over  the  walls.  As  heat  is  generated  in 
the  operation  of  the  engine,  a  circulation  of  air  is  set  up,  the  hot 
air  being  given  out  at  the  ends  of  the  tubes,  on  the  principle  of 
the  Bunsen  burner.  In  this  manner,  there  is  a  constant  supply 
of  cool  air  for  absorbing  the  heat  of  the  cylinder  and  the  circula- 
tion is  maintained  without  a  fan  or  other  mechanical  contrivance. 
The  Franklin  system  of  air  cooling  is  different  from  any  of 
the  fore  going  devices,  and,  judging  from  its  numerous  imitators, 


B  to.  148.— Cylinder  of  the  Regas  Engine,  showing  Bunsen  tubes  let  into  steel  jacket 

embodies  the  correct  principle  for  cooling  a  medium  to  heavy 
weight  gasoline  engine.  Briefly  described,  it  consists  in  using 
a  multiple  cylinder  engine ;  in  the  first  models  four  cylinders,  and 
latterly  six.  The  primary  effect  of  using  four  cylinders  is  that 
any  desired  degree  of  power  may  be  achieved  with  shorter  strokes 
and  smaller  pistons  than  would  be  possible  with  either  one  or 
two  cylinders.  The  area  of  the  combustion  space  being  reduced, 
the  heat  may  be  more  quickly  radiated  from  the  engine.  Frank- 
lin also  uses  a  supplementary  exhaust  situated  at  or  near  the  point 


196  SELF-PROPELLED  VEHICLES. 

of  piston  out-stroke,  so  as  to  be  uncovered  precisely  like  the  ex- 
haust port  in  a  two-cycle  engine.  The  supplementary  exhaust 
greatly  facilitates  the  expulsion  of  the  burnt  out  products  of  com- 
bustion. The  port  opens  into  a  small  chamber,  normally  closed 
by  a  poppet  valve,  which  is  opened  at  the  proper  moment,  thus 
giving  an  exhaust  from  both  top  and  bottom  of  the  cylinder. 
A  very  similar  arrangement  was  adopted  by  Fritscher  and  Houdry 
as  early  as  1900,  but  proved  only  indifferently  effected  on  a  single- 
cylinder  engine. 

Other  engines,  notably  the  Marion,  achieve  the  end  of  efficient 
air  cooling  by  using  an  exhaust  valve  of  unusually  large  area. 
Frayer  and  Miller  enclose  the  cylinders  of  their  engine  with  an 
air  jacket  through  which  air  is  forced  by  a  blower,  on  a  principle 
precisely  similar  to  water  circulation  forced  by  a  rotary  pump. 

Briefly  expressed  the  requirements  for  effective  air  cooling  are : 

1.  Radiating  surface,  large  in  proportion  to  the  outside  area 
of  the  cylinder. 

2.  Large  exhaust  valves,  or  some  mechanical  means  for  increas- 
ing the  speed  of  the  exhaust. 

3.  Combined  with  these  two,  a  multiple  cylinder  engine. 


CHAPTER    TWENTY-THREE. 

POWER  ELEMENTS  OP  A  GAS   ENGINE. 

Power  Efficiency  and  Fuel  Consumption.  —  As  we  have  al- 
ready learned,  there  are  various  conditions,  both  physical  and 
mechanical,  that  prevent  the  realization  of  the  full  theoretical  ef- 
fect of  the  heat  actually  expended  in  a  gas-engine  cylinder. 
Ideally  speaking,  the  efficiency  of  such  an  engine  should  be  ex- 
pressed by  this  formula  : 

Temperature  rise  in  degrees  _  T"  —  T' 

Explosion  Temperature  T" 

Substituting  the  average  figures  previously  found,  we  have  this 
expression  : 

3000—660       2340 

_  _  _  -—  __    —       yQ 

3000         "  3000 

This  would  involve  that  about  78  per  cent.,  on  the  average,  was 
the  actual  heat  efficiency  of  a  good  gas  engine.  The  results,  how- 
ever, are  far  below  this  ;  for,  even  allowing  for  all  the  apparently 
unavoidable  losses  in  the  process  of  transforming  heat  into  actual 
work,  we  find  that  the  real  average  makes  the  actual  mechanical 
efficiency,  in  terms  of  brake  horse-power,  about  80  per  cent,  of  the 
calculated  efficiency,  in  terms  of  indicated  horse-power.  Thus: 
B.  H.  P.  _  8  _ 
"  ~ 


I.    11.    P.  "  10 

This  is  generally  about  17  per  cent,  of  the  total  heat  expended, 
and  seldom  more  than  20  per  cent. 

Mechanical  Equivalent  of  Heat.  —  Now,  one  horse-power  is 
33,000  foot-pounds  per  minute,  and  778  foot-pounds  equals  one 
thermal  unit,  winch  equation  expresses  the  mechanical  equivalent 
of  heat.  Whence,  one.  horse-power  equals  42.42  thermal  units 
per  minute,  which  is,  by  the  hour,  2,545.2  thermal  units.  Then  a 
10  H.  P.  hour  equals  25,452  thermal  units  and  an  8  H.  P.  hour 
equals  20,361.60  thermal  units.  Whence  we  have: 

20361.6  __ 
25452 
197 


198  SELF-PROPELLED   VEHICLES. 

If,  however,  10  H.  P.,  or  25,452  B.  T.  U.  per  hour  be  assumed 
equivalent  to  the  I.  H.  P.  of  a  given  engine,  which  is,  as  a  general 
average,  26  per  cent,  of  the  total  heat  equivalent  supplied  to  the 
engine  in  the  shape  of  fuel,  we  have  it  that  the  total  theoretical 
value  of  the  fuel  should  be  97,892.31  B.  T.  U.,  or  38.46  H.  P. 

According  to  one  authority,  the  average  heat  expenditures 
found  in  a  number  of  tests  of  gas  engines  is  as  follows : 

To  the  jacket  water 52  per  cent. 

To  loss  in  the  exhaust 16  "       " 

To  loss  in  radiator,  etc 15  "       " 

To  useful  work  (B.  H.  P.) 17  "       " 

This  shows  a  total  of  83  per  cent,  lost  for  any  efficient  mechan- 
ical work  realized,  or  useful,  at  best,  only  for  maintaining  neces- 
sary interior  conditions.  Accepting  these  figures  as  fairly  typical, 
we  find  for  10  I.  H.  P.,  or  26  per  cent.,  a  total  of  97,892.31  thermal 
units,  or  the  heat  equivalent  of  38.46  H.  P.  by  the  hour  theo- 
retically, fed  to  the  cylinder  in  fuel  mixture. 

Then  reducing  the  above  table  to  terms  of  heat  equivalence,  we 
have: 

52%  =  50904.0x3  B.  T.  U.  —  20.000  H.  P. 
16%  =  15662.77  B.  T.  U.  =  6.154  H.  P. 
i7%  =  16641.69  B.  T.  U.  =  6.538  H.  P. 
15%  =  14683.85  B.  T.  U.  =  5.765  H.  P. 

100%  —  97892.31  B.  T.  U.  =  38.457  H.  P. 

Experimental  Figures. — Another  authority,  as  quoted  by  sev- 
eral writers,  finds  the  following  results  from  a  series  of  experi- 
ments with  a  125  H.  P.  gas  engine:  At  full  load  26  per  cent,  of 
the  heat  energy  is  converted  into  mechanical  energy,  44  per  cent, 
is  lost  through  the  exhaust  and  by  radiation,  and  30  per  cent,  is 
absorbed  by  the  jacket  water,  or  a  total  loss  of  74  per  cent.  At 
three-quarter  load,  the  figures  become  25,  38  and  37  per  cent.,  re- 
spectively, a  total  loss  of  75  per  cent;  at  one-quarter  load,  18,  28, 


POWER  ELEMENTS  OF  A  GAS  ENGINE.  199 

54,  a  total  loss  of  82  per  cent. ;  and,  when  running  free,  10,  32  and 
58  per  cent.,  a  total  loss  of  90  per  cent.  These  figures  show  that 
the  percentage  of  loss  through  the  exhaust  increases  as  the  jacket 
loss  decreases.  Other  recorded  tests  show  similar  figures. 

Calorific  Values  of  Fuels. — As  we  have  already  learned,  some, 
causes  of  lost  efficiency  lie  in  the  mechanical  constructions  at 
present  necessary  in  gas  engines;  others,  in  the  inevitable  waste 
due  to  the  operation  of  physical  laws  and  forces;  others,  again, 
in  improper  mixtures  and  defective  ignition  apparatus.  Other 
things  equal,  however,  the  kind  of  fuel  used  is  the  most  impor- 
tant consideration  in  securing  a  high  power  per  pound  of  fuel. 
This  is  particularly  emphasized  in  the  fact  that  the  various  sub- 
stances suitable  for  use  as  fuels  in  gas  engine  cylinders  differ 
greatly  in  calorific  values. 

As  given  by  reliable  authorities,  the  calorific  values  of  several 
common  hydrocarbon  fuels,  as  expressed  in  British  thermal  units, 
are  as  follows: 

Per  Pound.      Per  Cubic  Foot. 

Marsh  gas  (C  H4) 23,594  1,051 

Benzine  (C6  H6) 18,448 

Gasoline    21,900 

Acetylene  (C2  H2) 21,492 

Ethylene   (C2  H4) 21,430 

Natural  gas   

Illuminating  coal  gas 

Water  gas    (average) • 

Determining  Calorific  Values. — Knowing  the  specific  heat  of 
a  given  gas  at  constant  volume,  the  calorific  value  in  thermal 
units  may  be  discovered  as  follows,  in  order  to  estimate  the  ther- 
mal efficiency  of  an  engine : 

H=C  (T"-T'). 

In  this  formula  H  is  the  calorific  value  in  thermal  units ;  C,  the 
specific  heat  at  constant  volume ;  T",  the  temperature  of  explosion, 
and  T',  the  initial  temperature.  The  specific  heat  for  a  9  to  I 
mixture  of  air  and  coal  gas  being  0.1846;  a  typical  explosion  tem- 
perature 2,764  degrees,  absolute,  and  an  average  compression  tern- 


200  SELF-PROFELLED  VEHICLES. 

perature,  921  degrees,  we  have  340.21  thermal  units  per  pound  of 
the  initial  charge. 

Determining  the  Explosion  Pressure. — The  maximum  or 
explosion  pressure  of  a  gas  engine  is  equal  to  the  ratio  between 
the  compression  and  maximum  temperatures  multiplied  by  the 
compression  pressure.  Thus : 

Ct 

X  Cp  =  Ep. 

Et 
Substituting  the  values  given  above  for  a  given  engine,  we 

have: 

/2764        \ 

I =  3  )  X  68.86  =  206.58  pounds, 

V921         / 

which,  as  may  be  seen,  is  the  same  as  was  given  in  a  former 
chapter : 


T'. 

Horse»Power  in  Terms  of  Heat  Units. — In  order  to  estimate 
the  mechanical  efficiency  of  a  given  engine  we  must,  as  shown 
above,  know  the  delivered  horse-power.  While  there  are  num- 
erous ways  of  calculating  this,  the  simplest  and  readiest  formula 
for  a  one-cylinder  engine  is  as  follows : 
D8LE 

=  D.  H.  P. 

18,000 

This  means  that  the  square  of  the  piston  diameter,  D,  in  inches 
is  to  be  multiplied  by  the  length  of  the  stroke,  L,  in  inches  and 
the  number  of  revolutions  per  minute,  R,  of  the  fly-wheel,  and 
the  product  divided  by  18,000. 

The  denominator  18,000  is  given  by  Roberts  as  the  proper 
figure  for  a  four-cycle  gasoline  engine.  For  four-cycle  engines 
using  coal  gas,  the  denominator  would  be  19,000.  For  two- 
cycle  engines  using  gasoline,  the  denominator  would  be  13,500; 
for  other  types,  14,000. 

The  Delivered  Horse=Power. — To  apply  this  formula  we  will 
take  a  highly  efficient  three-cylinder  gasoline  vehicle  motor  with 


POWER  ELEMENTS  OF  A  GAS  ENGINE.  201 

proportions  as  follows :  The  piston  diameter  is  4.5  inches ;  the 
stroke  is  4.5  inches ;  the  number  of  revolutions  per  minute  is  900. 
Then,  substituting,  we  have: 

20.25  X  4.5  x  900       82,012.5 

-  = =  4.56  H.  P. 

18,000  18.000 

In  calculating  for  more  than  one  cylinder,- we  have  the  formula: 

D3LRN 

-  =  H.  P. 
18,000 

in  which  N  is  the  number  of  cylinders.  Hence,  for  three  cylin- 
ders : 

82,012.5  X  3 

=  13.67H.  P. 

18,000 

According  to  the  claims  of  the  manufacturer,  the  engine  in 
'juestion  yields  no  less  than  12  D.  H.  P.  by  actual  brake  tests. 

The  Time  Element  in  Power  Estimates. — In  the  determina- 
tion of  horse-power  the  rime  element  is  an  important  item,  be- 
cause the  power  to  be  calculated  produces  motion,  and  is  not  a 
static  pressure  to  be  measured  only  in  terms  of  pounds  weight. 
It  is  important  also  to  remember  that  the  power  efficiency  in- 
creases with  the  rate  of  motion,  being  expressed  in  terms  of 
revolutions  per  minute  of  the  fly-wheel  or  crank  shaft.  Thus,  a 
given  engine  running  with  low  gas  supply  or  high  load*  may  rotate 
the  fly-wheel  only  200  times  per  minute,  while,  with  full  gas  sup- 
ply, or  at  average  load,  it  can  produce  as  many  as  2,000  revolu- 
tions per  minute.  Furthermore,  the  available  power  decreases 
as  does  the  number  of  revolutions  per  minute,  while,  as  has  al- 
ready been  indicated,  the  rate  of  gas  consumption  per  unit  of 
work  is  increased.  Thus  it  is  important  to  know,  in  making  es- 
timates for  horse-power  whether  the  engine  in  question  is  running 
free  or  under  load. 

Engine  Dimensions  in  Power  Estimate. — Next  to  this,  the 
most  important  consideration  refers  to  the  dimensions  of  the 
piston  and  cylinder  and  the  length  of  the  stroke.  For,  since 
these  figures  indicate  the  power  capacity  of  the  engine,  in  point 


202  SELF-PROPELLED   VEHICLES. 

of  the  quantity  of  fuel  consumed,  and  the  power  developed  by 
explosion,  as  acting  on  the  reciprocating  parts,  they,  together 
with  the  ascertained  rate  of  motion,  are  in  ratio  to  a  figure  equiva- 
lent to  an  average  ratio  between  the  operative  dimensions  of  the 
cylinder — these  are  given  above  in  Roberts'  formula  for  D.  H.  P. 
— and  the  delivered  horse-power.  The  formula  is  further  verified 
in  the  fact  that  the  piston  diameter  and  length  of  stroke  are  in 
discoverable  proportion  to  the  D.  H.  P.  and  the  number  of  revo- 
lutions of  the  fly-wheel.  So  that  an  engine  giving,  say,  35 
D.  H.  P.  at  600  revolutions  per  minute,  with  a  fuel  whose  thermic 
value  is  known,  must  have  a  certain  diameter  of  piston  and 
length  of  stroke.  These  facts  will  be  evident  from  examination 
of  specimen  formulae. 

The  Indicated  Horse=Power. — In  making  more  definite  cal- 
culations on  the  power  of  a  gas-engine  there  are  four  points  to 
be  considered : 

i.  How  great  is  the  mean  effective  pressure  per  square  inch 
on  the  piston  during  the  power  stroke? 

2..  What  is  the  area  of  the  piston  ? 

3.  What  is  the  length  of  the  stroke? 

4.  What  is  the  number  of  explosions  per  minute? 

The  ratio  between  the  product  of  these  factors  and  33,000  gives 
the  I.  H.  P.  per  minute.  Thus : 

Pressure  x  area  x  stroke  X  E.  P.  M. 

-  =  I.  H.  P. 
33,000 

To  reduce  this  ratio  to  a  practical  formula  we  take  the  product 
of  the  mean  effective  pressure  of  the  power  stroke ;  by  the  area 
of  the  piston  in  square  inches;  by  the  length  of  the  stroke  in  feet ; 
by  the  number  of  explosions  per  minute,  and  divide  by  33,000, 
which  figure  expresses  the  number  of  foot-pounds  per  minute  per 
horse-power.  Thus : 

PASE 

-  =  I.  H.  P. 
33,000 

The  Mean  Effective  Pressure. — As  may  be  understood  from 
the  term  itself,  the  mean  effective  pressure  is  an  average  for  the 


POWER  ELEMENTS  OF  A  GAS  ENGINE.  203 

pressure  in  pounds  per  square  inch  brought  to  bear  upon  the 
piston  of  a  cylinder  during  the  power  stroke.  It  has  been  well 
defined  as  "the  difference  between  the  average  gauge  pressure 
shown  by  the  expansion  line  and  that  shown  by  the  compression 
line,  minus  the  back  pressure  of  charging  or  suction."  As  all 
these  operations  are  depicted  on  the  indicator  diagram  an  average 
of  its  proportions  will  yield  the  desired  result. 

The  Brake  Horse= Power. — The  most  satisfactory  method  of 
testing  the  effective  power  of  an  engine  is  by  the  use  of  Prony's 
brake,  one  form  of  which  is  shown  herewith.  Briefly,  it  consists 


FIG.  150.— Common  Form  of  Prony  Brake,  for  testing  the  D.  H.  P.  of  an  engine.  Ai> 
iron  band  shod  with  wooden  blocks  is  drawn  tightly  around  the  circumference  ot 
the  fly-wheel.  To  this  two  arms  are  attached,  the  other  ends  01  which  bear  upon 
the  scale  platform,  as  shown.  It  is  necessary  that  the  scale  platform  be  raised  to 
the  same  height  as  the  centre  of  the  fly-wheel  shaft. 

of  a  band  of  rope  or  strip  iron — the  latter  is  the  arrangement 
shown — to  which  are  fastened  a  number  of  wooden  blocks,  several 
carrying  shoulders  to  prevent  the  contrivance  from  slipping  off 
the  wheel  rim.  Being  applied  to  the  circumference  of  the  fly- 
wheel the  brake  band  is  drawn  tight,  as  shown,  so  that  the  blocks 
press  against  the  surface  all  around.  The  brake,  thus  formed,  is 
prevented  from  revolving  with  the  fly-wheel,  by  two  arms,  at- 
tached near  the  top  and  bottom  centres  of  the  wheel,  and  joined 
at  the  opposite  ends  to  form  a  lever,  which  bears  upon  an  ordinary 
platform  scale,  a  suitable  leg  or  block  being  arranged  to  keep  its 
end  opposite  to  the  centre  of  the  shaft.  By  this  arrangement  the 
amount  of  friction  between  the  brake  band  and  the  revolving 
wheel  is  weighed  upon  the  scales.  For,  since  the  brake  fits 


204  SELF-PROPELLED  VEHICLES. 

tightly  enough  to  be  carried  around  by  the  wheel,  but  for  the 
arms  bearing  upon  the  scale,  the  amount  of  frictional  power 
exerted  by  the  wheel  in  turning  free  within  the  blocks  ma,  be 
transmitted  and  measured,  just  as  would  be  the  case  were  a 
machinery  load  attached,  instead  of  a  friction  brake. 

Formula  for  Brake  Horse  Power.  —  The  net  work  of  the  en- 
gine or  horse  power  delivered  at  the  shaft  is  determined  as  fol- 
lows: 

Let  W  =  work  of  shaft,  equals  power  absorbed  per  minute. 

P  =  unbalanced  pressure  or  weight  in  pounds,  acting  on  the 
lever  arm  at  a  distance  L. 

L  =•  length  of  lever  arm  in  feet  from  centre  of  shaft. 

V  =  velocity  of  a  point  in  feet  per  minute  at  distance  L,  if  arm 
were  allowed  to  rotate  at  the  speed  of  the  shaft. 

N  =  number  of  revolutions  per  minute. 

B.  H.  P.  =  brake  horse  power. 

Then  will  W  =  PV  =  2        LNP. 

PV 

Since  B.  H.  B.  =—  —  , 
33000 

we  have  by  substituting  for  V. 


B.H.P.  = 

33000 


CHAPTER   TWENTY-FOUR. 


CARBURETTERS  AND  CARBURETTING. 

The  Carburetter  and  its  Use — Any  device  wherein  gasoline 
vapor  and  air  are  mixed  in  proper  proportions  to  form  the  fuel 
charge  for  an  internal  combustion  engine  is  called  a  carburetter 
or  vaporizer. 

Some  writers  make  a  distinction  between  the  two  words,  ap- 
plying the  word  "carburetter,"  when  in  addition  to  a  mixing 
chamber,  the  device  contains  a  receiving  chamber  for  the  gaso- 


FIG.  151. — The  first  carburetter  having  a  float  feed  for  maintaining1  the 
fuel  supply  at  constant  level;  introduced  by  Maybach.  A  is  the  hol- 
low float  carrying  the  spindle  of  the  needle  valve  at  its  top;  B,  the 
tube  leading  into  the  inlet  valve  space;  C,  the  spraying  nozzle;  D,  the 
inlet  valve;  E,  the  inlet  valve  spring;  F,  the  cylinder  space. 

line  and  means  of  maintaining  therein  a  constant  level  of  the 
fuel ;  the  word  "vaporizer"  being  applied  when  the  device  has  no 
receiving  chamber ;  as,  a  generator  valve. 

Gasoline  is  a  liquid  which  has  a  very  low  boiling  point  and 
which  constantly  evaporates  even  at  ordinary  temperatures,  satu- 
rating the  air  with  its  vapor.  On  account  of  this  property  of 
gasoline  the  carburetter  accomplishes  the  mixing  by  rapidly 
bringing  a  comparatively  large  volume  of  air  into  intimate  con- 
tact with  a  quantity  of  gasoline  in  the  form  of,  i,  a  spray  or,  2,  by 
surface  contact. 

800 


206  SELF-PROPELLED   VEHICLES. 

The  carburetter  should  so  regulate  the  supply  of  air  and  gaso- 
line that  the  resulting  mixture  will  always  contain  the  two  in- 
gredients in  the  proper  proportions.  There  must  not  be  too 
much  gasoline  vapor,  as  fuel  would  be  wasted  either  by  being 
decomposed  into  soot  or  unburned  on  account  of  there  not  being 
enough  air  to  consume  it.  On  the  other  hand  too  much  air,  even 
though  the  mixture  should  ignite,  would  lower  the  temperature 
of  combustion  and  thus  diminish  the  useful  expansion.  Inability 
to  start  the  engine,  to  speed  up,  or  to  run  as  slowly  as  one  would 
like  may  all  be  due  to  either  too  little  or  too  much  gasoline. 
Hence  the  importance  of  maintaining  the  supply  of  gasoline  and 
air  in  correct  proportions. 

Varieties  of  Carburetter- — Classified  according  to  structure 
and  operation,  there  are  three  varieties  of  carburetting  apparatus : 

1.  The  sprayer  carburetter,  in  which  the  liquid  hydrocarbon  is 
sprayed  or  atomized  through  a  minute  nozzle  and  mixed  with  a 
passing  column  of  air. 

2.  The  surface  carburetter,  operating  to  produce  a  fuel  mix- 
ture when  air  is  passed  over  the  surface  of  a  body  of  liquid  hydro- 
carbon, or  circulated  around  a  gauze,  wicking  or  metal  surface 
saturated  with  such  a  liquid. 

3.  The  ebullition  or  filtering  carburetter,  in  which  air  is  forced, 
under  suction,  through  a  body  of  liquid,  from  bottom  to  top,  so 
as  to  absorb  particles  of  its  substance. 

Of  these  types,  the  first  and  second  only  have  been  widely  used 
with  automobile  engines.  The  sprayer  is  now  the  prevailing 
form. 

In  the  present  stage  of  the  carburetter  art  the  non-automatic 
type  of  carburetter  may  be  ignored  and  the  automatic  carburetter 
broadly  classified  into  the  sprayer  and  surface  or  "puddle" 
types. 


NOTE. — The  fuel  charge  for  a  gas  engine  consists  of  auout  ten  to  sixteen 
parts  air  to  one  of  gasoline  vapor.  The  proportion  varies  according 
to  the  conditions  of  the  atmosphere,  quality  of  gasoline  and  engine 
speed. 


CARBURETTERS  AND  CARBURETTING. 


207 


Carburetter  Principles — Owing  to  certain  characteristic  dif- 
ferences in  behavior  it  will  be  best  to  treat  the  sprayer  and  sur- 
face types  separately.  First  consider  the  simplest  form,  or  what 


FIG.  152. — A  rudimentary,  or  simple  form  of  spray  carburetter  Illustrat- 
ing the  principles  of  operation  employed  in  the  modern  device.  A,  Is 
the  receiving  chamber;  B,  the  mixing  chamber.  A  connecting  pas- 
sage conveys  fuel  to  the  spray  nozzle  C,  controlled  by  the  needle 
valve  D,  by  turning  the  thumb  wheel  E.  Air  enters  through  the  pri- 
mary passage  in  the  base  and  through  the  auxiliary  ports  F,  the  lat- 
ter being  adjustable  by  the  sleeve  G,  and  the  mixture  to  the  engine, 
controlled  by  a  throttle  located  above  the  sleeve. 


may  be  called  a  rudimentary  carburetter  having  a  sprayer  and 
means  of  regulating  the  mixture  by  hand  as  shown  in  Fig.  153. 


208  SELF-PROPELLED    VEHICLES. 

The  drawing  illustrates  a  receiving  chamber  A  and  a  mixing 
chamber  B,  the  two  being  connected  by  a  small  passageway  or 
duct  which  terminates  at  the  sprayer  C,  made  adjustable  by  the 
needle  valve  D.  The  lower  end  of  the  mixing  chamber  B  is 
open  to  the  atmosphere,  while  the  upper  end  is  provided  with 
auxiliary  air  ports  F,  having  a  collar  or  sleeve  G  with  which  to 
adjust  the  opening  of  the  ports  to  the  atmosphere. 

In  explaining  the  action  of  this  rudimentary  carburetter,  it  is 
necessary  to  assume  the  receiving  chamber  A  to  be  filled  with 
gasoline  to  a  level  MN,  very  near  the  elevation  of  the  spray  noz- 
zle, and  also  to  assume  the  supply  replenished  as  it  is  used  so  that 
the  fluid  level  MN  is  maintained. 

Now,  suppose  the  upper  end  of  the  mixing  chamber  to  be  con- 
nected with  an  engine  as  indicated.  Each  intake  stroke  of  the 
engine  will  displace  a  volume  of  air,  causing  a  partial  vacuum  in 
the  mixing  chamber  B ;  the  intensity  of  the  vacuum,  as  will  be 
seen,  depending  on  the  engine  speed.  Assuming  the  engine  to  be 
working  at  slow  speed  with  a  heavy  load  and  the  auxiliary 
ports  F  closed  by  the  sleeve  G,  the  gasoline  supply  may  be  ad- 
justed by  the  needle  valve  E  so  that  the  engine  will  receive  from 
the  carburetter  a  mixture  containing  the  proper  proportion  of 
gasoline  vapor  and  air. 

If  now  part  of  the  load  on  the  engine  be  removed  so  that  it  will 
run  say  twice  as  fast,  the  same  amount  of  air  and  gasoline  for 
each  charge  must  be  received  by  the  engine  in  one-half  the  time. 
Under  these  conditions  the  mixture  would  become  too  rich,  that 
is,  too  much  gasoline  would  be  fed  for  the  amount  of  air  passing 
through  the  inlet  at  the  lower  end  of  the  mixing  chamber.  The 
excess  of  gasoline  is  due  to  the  fact  that  in  order  to  get  twice 
the  amount  of  air  through  the  inlet  the  suction  has  to  be  more 
than  doubled  to  compensate  for  the  increased  frictional  resistance 
set  up  by  the  higher  velocity  of  the  air  passing  through  the  inlet 
The  suction,  or  degree  of  vacuum  in  the  carburetter,  being  more 
than  doubled,  it  naturally  follows  that  more  than  double  the 


CARBURETTERS  AND  CARBURETTING. 


209 


amount  of  gasoline  will  pass  through  the  spray  nozzle.  This  ex- 
cess of  vacuum  is  caused  by  the  expansion  of  the  air  in  entering 
the  carburetter,  increasing  its  velocity  after  expansion  more  than 
two-fold. 

In  order  to  maintain  the  mixture  in  the  same  proportions  for 
varying  demands,  it  is  necessary  to  provide  some  means  to  keep 
the  suction  or  degree  of  vacuum  in  the  mixing  chamber  constant. 
The  suction  may  be  restored  to  its  normal  condition  by  slightly 


FIG.  IBS.— A  simple  form  of  float  feed,  with  float  concentric  to  inlet  valve. 

raising  the  sleeve  G  so  as  to  partially  open  the  auxiliary  air  ports 
F.  This  allows  some  air  to  enter  through  the  auxiliary  ports, 
thus  reducing  the  velocity  of  the  entering  air  and  relieving  some- 
what the  suction  at  the  lower  inlet.  The  amount  of  opening  of 
the  auxiliary  air  ports  necessary  for  any  change  of  engine  speed 
may  be  found  by  experiment. 


By  placing  a  throttle  valve  in  the  passage  B  between  the  aux- 
iliary ports  and  the  engine  the  load  may  be  altered  without  any 
variation  in  the  engine  speed  by  adjusting  the  throttle  opening. 


210 


SELF-PROPELLED   VEHICLES. 


In  actual  construction,  automatic  devices  are  employed  to  maintain  the 
gasoline  in  the  float  chamber*  at  constant  level  and  to  adjust  the  auxiliary 
port  openings  to  different  engine  speeds. 

It  has  been  shown  that  the  feeds  of  gasoline  and  air  do  not  vary  in  the 
same  proportion  when  the  suction  varies.  A  second  reason  for  this  irreg- 
ularity is  the  fact  that  an  initial  suction  is  required  to  lift  the  gasoline  to 
the  mouth  of  the  nozzle,  before  spraying  can  begin.  The  slightest  suction 
only  is  required  to  draw  air  through  the  air  inlet ;  there  is,  however,  a  cer- 


PIG.  154.— A  form  of  float  feed  In  which  provision  Is  made  for  adjusting 
tbe  fuel  level  by  means  of  a  spring  nut  R. 

tain  minimum  suction  below  which  no  gasoline  can  be  fed,  depending  on 
the  difference  in  the  level  of  the  supply  and  the  level  of  the  spray  nozzle. 
Hence,  the  importance  of  eliminating  this  difference  in  level  is  readily  seen. 
The  first  requirement  of  a  carburetter  may  be  said  to  be  the  maintenance  of 
the  gasoline  supply  in  the  float  chamber  at  practically  the  same  elevation 
as  that  of  the  spray  nozzle. 

*In  discussing1  the  modern  carburetter,  the  term  float  chamber  Is  used 
instead  of  receiving  chamber  as  it  is  generally  known  by  that  name, 
since  a  float  Is  almost  always  used  to  regulate  the  flow  of  gasoline  into 
th*  chamber. 


CARBURETTERS    AND    CARBURETT1NG. 


211 


Float  Feed. — Of  the  different  devices  used  to  maintain  the 
gasoline  supply  at  constant  level  in  the  float  chamber,  what  is 
known  as  a  float  feed  has  been  adopted  by  almost  all  makers,  with 
the  result  that  at  the  present  day  its  use  is  world  wide. 

Where  departures  from  the  system  have  been  made,  they  usually 
consist  of  some  form  of  overflow  arrangement  whereby  the  gaso- 
line is  maintained  at  the  necessary  level  by  a  surplus  volume  being 
pumped  or  otherwise  forced  into  a  chamber  whence  the  overflow 
returns  to  the  main  supply,  the  height  and  capacity  for  the  return 


FIG.  155. — This  Illustrates  a  construction  of  float  feed  In  which  the  fuel 
level  Is  made  adjustable  by  the  use  of  a  variable  counterweight  P. 

of  the  overflow  maintaining  the  necessary  level  with  reference  to 
the  spray  nozzle. 

A  float  feed  device  consists  of  a  cork  or  hollow  metal  float 
placed  in  the  float  chamber.  It  is  connected  so  as  to  operate  the 
gasoline  inlet  valve,  usually  by  means  of  levers.  These  are  ar- 
ranged in  such  a  manner  that,  as  gasoline  enters  the  float  chamber 
through  the  inlet  valve,  the  float  rises,  and  in  so  doing,  closes  the 
valve  thus  shutting  off  the  supply  when  the  gasoline  reaches  the 
desired  level. 


213  SELF-PROPELLED    VEHICLES. 

In  different  makes  of  carburetters  this  level  varies  from  about 
Y&  to  }4  mch  below  the  top  of  the  spray  nozzle;  to  be  accurate, 
the  level  should  be  such  that  the  liquid  will  form  a  bubble  at 
the  nozzle  to  be  blown  off  at  will,  and  the  exact  height  should  be 
found  by  this  method  when  the  construction  will  permit. 

There  are  many  forms  of  float  feed.  Fig.  153  shows  a  simple 
arrangement.  The  float  is  constructed  concentric  with  the  inlet 
valve  A.  In  the  bottom  of  the  float  chamber  is  a  small  tube 
through  which  the  gasoline  must  flow  to  the  spray  nozzle.  The 
object  of  this  tube  is  to  prevent  small  particles  of  dirt  and  bubbles 
of  water  that  may  be  in  the  gasoline  from  entering  the  spray  noz- 
zle. The  plug  B  at  the  bottom  of  the  float  chamber,  where  the 
fuel  flows  to  the  spray  nozzle,  is  provided  with  a  fine  wire  screen 
to  catch  any  foreign  matter  that  may  be  in  the  gasoline  in  order 
that  it  may  not  lodge  in  the  spray  nozzle  and  impede  the  flow  of 
the  liquid. 

Fig.  154  represents  a  more  refined  design.  The  fuel  level  may 
be  adjusted  by  means  of  the  spring  nut  R.  At  F  is  located  a 
strainer  which  can  be  easily  taken  out.  Fig.  155-  shows  a  con- 
struction which  is  very  much  employed  owing  to  the  great  facility 
with  which  the  fuel  level  can  be  adjusted.  To  this  end  the  coun- 
terweight P  is  either  increased  or  diminished. 

In  order  to  obtain  uniform  results,  especially  where  a  car  is 
operated  on  hilly  roads,  the  float  chamber  with  its  float  should  be 
constructed  concentric  with  the  spray  nozzle  so  that  any  inclina- 
tion of  the  car,  in  ascending  or  descending  a  hill  will  not  tlisturb 
the  gasoline  level  with  reference  to  the  nozzle.  This  principle  is 
utilized  in  the  construction  of  many  carburetters  as  shown  in 
Fig.  156. 

The  importance  of  this  becomes  plain  by  again  referring  to 
Fig.  152.  Here,  the  line  MN  represents  the  normal  height  of 
the  gasoline  when  the  carburetter  is  level. 

Now,  suppose  the  carburetter  to  be  inclined  so  that  the  line 
M'N'  or  M"N"  becomes  horizontal.  These  lines  then  repre- 
sent, respectively,  the  level  of  the  gasoline,  with  reference  to  the 


CARBURETTERS  AND  CARBURETTING,  213 

spray  nozzle,  for  the  two  inclined  positions  of  the  carburetter. 
Hence,  it  is  evident  that  the  gasoline  level  would  be  either  too 
high  or  too  low  with  respect  to  nozzle  while  remaining  undis- 
turbed at  the  float  center. 

The  Float. — This  is  one  of  the  important  parts  in  the  make-up 
of  a  carburetter  and  any  imperfection  will  produce  a  marked  ef- 


FrC.  156. — Type  of  carburetter  having  the  float  arranged  concentric  with 
the  spray  nozzle.  This  construction  eliminates  the  disturbance  of 
the  fuel  level  with  respect  to  the  nozzle  which  otherwise  would  be 
caused  by  any  inclination  of  the  car. 

feet  on  the  quality  of  the  mixture.  The  material  of  which  the 
float  is  made  consists  usually  of  cork  or  metal.  Owing  to  the 
nature  of  its  work  it  is  a  part  which  sometimes  causes  trouble ; 
cork  floats  are  liable  to  become  saturated  with  gasoline  thus  los- 
ing their  buoyancy,  while  those  made  of  metal  are  liable  to  leak. 
Of  whatever  material  it  is  made,  the  float  should  remain  constant 


214  SELF-PROPELLED    VEHICLES. 

in  weight  and  buoyancy.  When  made  of  metal,  the  float  should 
be  preferably  without  working  joints,  and  particularly  without 
frictional  contacts  with  levers,  which  may  sooner  or  later  wear 
through  its  thin  metal  and  cause  a  leak. 

The  float  point  is  usually  made  adjustable  as  before  shown, 
so  that  the  level  of  the  liquid  may  be  maintained  at  the"  most  ad- 
vantageous point  with  respect  to  its  proper  discharge  from  the 
spray  nozzle.  To  secure  a  constant  level  the  float  point  must  be 
adjusted  for  different  grades  of  gasoline,  as  the  level  of  the  float 
depends  upon  the  specific  gravity  of  the  liquid. 

Some  authorities  consider  it  bad  practice  to  balance  floats  by 
weights,  in  addition  to  the  column  of  liquid  in  the  float  chamber, 
for,  owing  to  their  different  densities,  the  liquid  and  the  weights 
may  interfere  in  their  duties  and  destroy  the  perfect  balance 
sought  for. 

It  is  advisable  that  the  float  chamber  should  open  at  the  bot- 
tom. This  facilitates  removal  of  any  water,  ice  or  dirt,  and  re- 
moval of  float  itself,  without  opening  the  top  and  permitting  dirt 
to  fall  in  from  above.  The  float  and  removable  bottom  can  be 
replaced  with  a  stream  of  gasoline  flowing  upon  them,  which  will 
wash  away  particles  of  dirt,  if  any  accidentally  get  on  the  parts 
while  being  replaced.  With  top  opening,  ice  in  the  bottom  of 
the  chamber  may  not  only  support  the  float  and  prevent  its  falling 
to  admit  gasoline,  but  may  also  bind  the  float  so  firmly  that  it  can- 
not be  removed  to  permit  removal  of  ice,  which  may  prove  an  un- 
pleasant predicament  if  away  from  means  of  warming  the  car- 
buretter. 

Gasoline  should  enter  the  float  chamber  from  a  single  direction, 
either  up  or  down,  so  that  no  pockets  exist  in  which  water  or  dirt 
may  gather. 

The  inlet  needle  valve  may  be  kept  tight  and  in  perfect  work- 
ing order  by  occasional  grinding  and  to  facilitate  this,  the  con- 
struction of  the  carburetter  should  be  such  that  the  valve  is  easily 
accessible.  Further,  the  motion  of  the  car  should  tend  to  move 


CARBURETTERS  AND  CARBU RETTING.  215 

the  valve  to  some  degree,  even  though  slight,  which  movement 
serves  to  force  away  any  particles  of  dirt  that  may  lodge  on  the 
point  during  the  passage  of  the  liquid.  On  this  account  it  is  best 
if  the  float  and  valve  be  fixed  one  to  the  other  so  that  the  point 
partakes  of  the  motion  of  the  float  and  liquid  in  the  chamber. 

The  float  chamber  is  provided  with  an  air  vent  to  prevent  the 
accumulation  of  any  excess  pressure  which  would  interfere  with 
the  proper  flow  of  the  gasoline. 

There  is  on  top  of  the  float  chamber  a  pin  or  "tickler,"  as  it  is 
called.  This  is  a  device  for  depressing  the  float  to  obtain  an  ex- 
cess of  gasoline  when  such  is  required  for  starting  the  engine. 
Some  motorists  regard  it  as  a  necessary  preliminary  to  starting, 
to  "tickle  the  carburetter,"  but  carburetters  differ;  with  some  it 
is  necessary  that  the  level  in  the  float  feed  chamber  be  high,  in 
others  not  so  high.  Some  carburetters  flood  easily,  while  others 
never  flood.  It  is  as  difficult  to  start  on  an  over  rich  mixture  as 
it  is  with  a  thin  one.  Any  small  tickling  of  the  carburetter  serves 
to  start  the  nozzle  and  create  a  small  amount  of  mixture.  But 
this  process  soon  floods  the  carburetter,  and  as  the  quantity  of  air 
supplied  is  small  and  cannot  be  increased  to  any  great  extent  be- 
fore the  motor  starts,  flooding  is  apt  to  fill  the  inlet  manifold  with 
almost  pure  gasoline  vapor  and  the  motor  will  not  start. 

Many  motors  will  start  without  touching  the  carburetter,  and 
in  the  case  of  others  the  process  of  starting  is  rendered  far  easier 
by  the  moderate  application  of  attention  of  this  sort. 

In  priming  a  carburetter,  the  tickler  should  be  depressed  and 
held  down  for  a  few  seconds.  This  will  cause  as  much,  if  not 
more,  gasoline  to  enter  in  a  given  space  of  time,  than  if  the  tick- 
ler be  worked  like  a  pump.  The  latter  operation  as  frequently 
performed  is  liable  to  injure  the  float. 

Usually  the  tickler  is  arranged  to  pass  down  to  the  float  through 
the  air  vent  tube. 

Since  gasoline  has  considerable  weight,  and  consequent  inertia, 
the  passage  to  the  nozzle  should  be  both  short  and  large,  for 


216 


SELF-PROPELLED    VEHICLES. 


large  passages  do  not  clog  easily  and,  if  short,  the  liquid  will 
respond  more  promptly  to  the  suction.  If  the  passage  be  large, 
the  friction  is  less,  on  account  of  reduced  velocity  of  flow. 

On  the  other  hand,  should  this  passage  be  long,  the  effect  of 
inertia  is  more  marked  causing  the  liquid  to  respond  less  quickly 
to  the  suction,  the  strength  of  which  changes  rapidly  during  each 
intake  stroke. 


FIG.  137.— The  Duryea  Carburetter.  The  gate  A  Is  placed  In  the  air  passage  hinged 
to  the  hollow  rod  B  of  the  piston  C.  The  suction  of  the  engine  lifts  C  and  A, 
opening  the  air  passage  as  needed.  Above  C  is  a  radius  link  E,  throuKh  which 
the  spiral  portion  of  the  gasoline  valve  spindle  P  passes.  As  C  raises,  this  link  E 
turns  P,  which  being  threaded  in  D  adjusts  the  gasoline  to  the  air  then  passing. 
This  action  of  E  may  be  adjusted  by  changing  the  position  of  the  pivoted  end  of 
E  carried  by  the  holder  H,  so  that  the  working  point  of  E  makes  either  a  long  arc 
with  much  needle  movement,  or  a  short  arc  with  little  needle  movement  as  C 
rises.  The  original  adjustment  for  starting  is  secured  by  turning  D  till  perfect 
mixture,  slowest  speeds  and  easiest  starts  are  obtained. 


On  account  also  of  this  inertia  effect,  the  liquid  does  not  get 
started  until  a  considerable  volume  of  air  has  passed  the  nozzle, 


CARBURETTERS  AND  CARBURETTING. 


217 


making  the  early  part  of  the  charge  too  lean.  Now,  as  the  suc- 
tion decreases,  the  interia  of  the  liquid  causes  it  to  continue  to 
flow,  making  the  latter  portion  of  the  charge  too  rich  and  proba- 
bly leaving  between  charges  unsprayed  drops  of  liquid  which 
either  fall  upon  the  walls  of  the  carburetter,  or  are  drawn  into 
the  engine. 

Disc  Feed — In  the  disc  feed  the  air  is  drawn  through  a  pas- 
sageway containing  a  minute  fuel  opening.  This  opening  is 
closed  by  a  needle  valve  which  has  a  disc  of  very  thin  sheet  metal 


FlO.  158.— Some  different  forms  of  spray  nozzles :  (a),  a  simple  form  with  single  open 
Ing ;  (b),  a  nozzle  consisting  of  a  series  of  slots ;  <o),  multi-slot  nozzle  easily  remov- 
able without  the  use  of  tools. 

attached  to  the  stem.     When  no  air  is  passing  through  the  car- 
buretter, the  needle  valve  closes  the  gasoline  nozzle. 


As  soon  as  air  is  drawn  through,  the  current  striking  against 
the  disc,  lifts  it  from  its  seat.  Gravity  and  suction  then  both 
bring  gasoline  out  of  the  nozzle  to  mix  with  the  air.  The  lift  of 
the  valve  and  its  disc  are  controlled  by  an  adjustable  screw  which 
regulates  the  extent  of  the  movement. 


218  SELF-PROPELLED    VEHICLES. 

Diaphragm  Feed — This  mode  of  regulating  the  gasoline 
supply,  depends  on  the  action  of  reduced  air  pressure  on  a  dia- 
phragm supported  at  its  circumference,  and  free  to  move  at  the 
center.  The  needle  valve  for  controlling  the  supply  of  gasoline 
is  held  on  its  seat  when  no  air  is  passing.  As  soon  as  air  is 
drawn  through  the  carburetter,  the  pressure  is  reduced  on  one 
side  of  the  diaphragm ;  this  causes  its  center  to  move.  The  needle 
valve  being  attached  to  its  center,  is  lifted  from  its  seat,  which 
allows  gasoline  to  flow  either  by  gravity  or  suction,  or  both. 
Sometimes  a  piston  is  used  instead  of  a  diaphragm,  as  in  the 
Duryea  Carburetter  illustrated  in  fig.  1 57. 

The  Spray  Nozzle. — In  the  carburetter,  the  fuel  is  discharged 
into  the  mixing  chamber  through  a  fine  orifice  called  the  spray 
nozzle.  This,  as  its  name  implies,  is  intended  to  deliver  the 
liquid  in  the  form  of  a  fine  spray,  which  is  subsequently :  i,  vapor- 
ized more  or  less ;  2,  mixed  with  the  entering  air,  and  3,  carried 
by  the  suction  into  the  engine  cylinder. 

The  simplest  form  of  spray  nozzle  is  one  having  a  single  open- 
ing, as  shown  in  fig.  158-a. 

The  spraying  effect  in  this  simple  form  is  less  marked  than 
that  obtained  with  nozzles  having  a  number  of  slots  as  illustrated 
in  fig.  158-b.  However,  with  the  single  nozzle,  there  is  less  danger 
of  it  becoming  clogged.  The  operation  of  a  multi-slot  nozzle  is 
undoubtedly  better  than  one  with  a  single  opening,  but  it  is  nec- 
essary for  the  construction  to  be  such  that  it  may  be  readily  with- 
drawn in  order  to  clean  the  small  spray  slots. 

Fig.  158-0  illustrates  a  construction  of  this  kind  which  permits 
the  removal  of  the  nozzle  without  the  use  of  tools,  it  only  being 
necessary  to  unscrew  the  milled  nut,  and  the  whole  nozzle  comes 
out  with  it.  The  amount  of  liquid  passing  through  the  nozzle 
may  be  varied  by  an  adjustable  needle  or  metal  rod  having  a  coni- 
cal point.  The  spraying  qualities  of  the  nozzle  with  a  single 
opening  fig.  158-3,  are  improved,  when  fitted  with  a  conical 
pointed  needle  working  from  above. 


CARBURETTERS  AND  CARBURETTING. 


219 


Multiple  Nozzles. — Some  carburetters  are  provided  with  more 
than  one  nozzle,  two,  three  or  more  being  employed.  Multiple 
nozzles  are  well  adapted  for  high  powered  machines.  Car- 
buretters with  multiple  nozzles  are  sometimes  so  constructed  that 
the  several  nozzles  forming  the  unit,  come  into  action  progres- 
sively as  the  power  demand  increases,  producing  the  same  effect 
as  though  several  separate  carburetters  were  used,  each  being 
brought  into  action  successively. 


FIG.  150.— The  Winton  Multiple  Nozzle  Carburetter.  It  has  two  nozzles 
and  is  a  modification  of  the  surface  venturi  tube  type,  consisting  of 
a  large  and  a  small  tube  placed  side  by  side  above  the  float  chamber. 
These  tubes  are  bent  downward  at  their  middle  so  that  small  puddles 
of  gasoline  are  formed  at  their  smallest  diameters  when  the  engine 
is  idle.  When  it  is  running  the  fuel  supply  may  be  regulated  by 
needle  vaives  D.  Connection  to  the  engine  is  made  at  A.  Butterfly 
valves  B  and  C  serve  as  throttles.  When  starting  C  is  closed,  and 
all  the  mixture  is  drawn  through  the  small  opening  in  B.  E  serves  to 
muffle  the  noise  of  suction  and  to  prevent  foreign  substances  from 
being  drawn  into  the  carburetter. 


The  needle  valve  which  regulates  the  supply  of  fuel  at  the 
nozzle  should  have  suitable  connections  so  that  it  may  be  ad- 
justed by  the  operator  and  enable  him,  while  operating  the  car, 
to  vary  the  proportion  of  the  mixture,  and  thus  secure  the  greatest 
power  by  trial,  as  well  as  to  accommodate  the  device  to  the  tern- 


220  SEIF-PROPEILED   VEHICLES. 

perature  and  humidity  of  different  days,  and  also  to  the  gravity 
of  different  grades  of  fuel.  No  adjustment,  while  the  car  is  stand- 
ing, can  compare  with  adjustments  in  actual  road  service  in  point 
of  accuracy. 

Further,  the  carburetter  should  be  adjustable  at  low  speeds,  to 
secure  certain  ignition  and  steady  running.  Gas  engines  are  apt 
to  misfire  at  their  limits,  and  the  perfect  carburetter  for  automo- 
biles will  provide  superior  conditions  at  these  limits  in  order  to 
secure  the  most  satisfactory  range  of  service.  This  necessitates 
provision  also  for  adjustment  at  normal  or  high  speeds. 

Gasoline,  as  it  is  sucked  out  of  the  nozzle,  made  up  as  it  is,  of  hydrocar- 
bons of  differing  values,  from  the  point  of  view  of  weight  and  volatility, 
will  hold  to  the  globular  form  with  more  or  less  tenacity,  depending  upon 
conditions. 

It  should  be  noted  that  doubling  the  diameter  of  these  globules  increases 
their  surface  four  times,  but  their  bulk  will  be  increased  eight  times. 
Evaporation  is  proportional  to  the  surface,  but  if  double  the  quantity  re- 
side under  a  given  surface,  double  the  time  must  be  taken  to  gasify  the 
liquid,  subject  to  a  correction  in  that  the  spheroids  are  reducing  in  diame- 
ter as  the  vapor  expands.  Hence,  the  importance  of  constructing  the  noz- 
zle so  that  it  shall  discharge  gasoline  in  as  finely  a  divided  state  as  possible. 

In  any  one  carburetter  the  perfection  of  vaporization  is  proportioned  to 
the  fineness  with  which  the  liquid  is  broken  up  at  the  nozzle.  The  short- 
ness of  the  time  within  which  vaporization  must  be  completed  is  what 
causes  the  above  factor  of  fineness  of  division  to  enter.  Since  the  heat 
transfer  between  the  air  and  the  liquid,  or  the  passage  walls  and  the  liquid, 
is  effected  chiefly  through  the  agencies  of  convection  and  conduction — the 
former  implying  a  rapid  agitation  and  relative  motion  between  the  particles 
of  the  two  substances,  and  the  latter  the  exposure  by  the  liquid  of  the 
greatest  possible  surface  areas — it  is  readily  seen  that  the  finer  the  fuel 
division  at  the  nozzle  the  more  rapid  and  complete  will  be  the  vaporization 
and  the  greater  the  homogeneity  of  the  final  mixture. 

Those  who  have  constructed  transparent  mixing  chambers  for  the  ob- 
servance of  nozzle  action  have  ascertained  that  the  fuel  left  the  nozzles 
as  a  solid  stream  or  in  heavy  globules  and  irregular  "chunks,"  not  as  a 
fine  spray  or  mist,  as  it  is  supposed  to  do. 

A  good  design  of  nozzle  and  needle  will  do  much  to  correct  this  faulty 
action  with  an  increase  in  power  output  and  fuel  economy.  However,  any 


CARBURETTERS   AND    CARBURETTING. 


221 


nozzle  form  used  will  give  a  wet  and  uneven  discharge  with  low  engine 
demands,  even  though  a  true  spray  may  be  delivered  with  increased  de- 
mands. 

Whatever  form  be  given  to  the  nozzle,  the  effectiveness  with  which  it  can 
break  up  the  fuel  varies  as  the  difference  between  the  pressures  at  its  two 
ends,  and  as  this  pressure  difference  varies  throughout  the  speed  range  of 
the  engine,  the  fineness  will  also  vary.  Since  the  nozzle  has  a  very  small 
opening,  even  for  the  largest  automobile  motors,  it  is  easily  stopped  up, 
and  the  construction  should  be  such  as  to  enable  one  to  remove  the  nozzle 
for  purposes  of  cleaning,  without  too  much  trouble. 


Fio.  160.— The  Mixing  Chamber  with  Its  appendages.  Illustrating,  In  general, 
the  arrangement  of  parts,  the  primary  and  auxiliary  air  passages;  auxiliary 
valve,  spring  and  adjustment;  the  ppray  nozzle  with  needle  valve  and  the 
throttle  valve.  The  arrows  indicate  the  direction  of  the  entering  air  currents 
and  course  of  mixture. 

The  Mixing  Chamber. — This  consists  of  a  small  enclosure  or 
passageway  containing  the  spray  nozzle.  The  mixing  chamber, 
as  its  name  implies,  is  the  place  where  gasoline  and  air  are 
brought  together  in  proper  proportions  and  commingled  to  form 
the  fuel  charge  for  the  engine.  It  is  provided  with  a  main  "air 
inlet  and  auxiliary  air  ports  as  before  described  but  the  latter  ar- 
ranged to  operate  automatically. 


222 


SELF-PROPELLED    VEHICLES. 


The  outlet  to  the  engine  is  fitted  with  a  throttle  valve,  permit- 
ting the  quantity  of  the  mixture  to  be  varied  as  desired. 

The  construction  of  the  mixing  chamber  with  its  appendages 
follows  substantially  the  arrangement  shown  in  fig.  160.  This 
illustrates  a  mixing  chamber  with  the  spray  nozzle  A  located  in 
the  center.  The  adjustable  needle  valve  E  regulates  the  flow  of 
gasoline  to  the  nozzle.  The  mixing  chamber  is  open  to  the  at- 
mosphere at  its  lower  end  D,  through  which  the  primary  or  main 


Fio.  161.— The  G  and  A  (Grouvelle  and  Arquembourg)  Carburetter.  French  make  of 
the  venturi  tube  type.  In  operation,  air  enters  the  primary  inlet  E,  mixing  with 
the  gasoline  at  G  which  ia  fed  from  the  float  chamber  C— Ihe  fuel  level  being 
maintained  by  the  float  F.  The  auxiliary  air  supply  enters  at  B  through  the  open- 
Ings  O,  arranged  concentric  with  the  mixing  chamber  and  consisting  of  a  ball  cage 
which  is  pierced  with  holes  of  different  sizes,  these  being  stopped  by  balls  of  dif. 
ferent  diameters  and  weights.  As  the  speed  of  the  engine  increases  and  a  greater 
amount  of  air  is  required,  the  lightest  ball  lifts,  allowing  a  certain  amount  of  air 
to  slip  by  it.  As  the  speed  is  further  increased,  other  balls  lift  and  progressively 
Increase  the  area  of  the  air  space.  The  outlet  A  is  controlled  by  a  throttle  D  oper- 
ated by  the  lever  M.  A  heating  jacket  is  provided,  encircling  the  throttle  as  illus- 
trated in  the  figure. 


CARBURETTERS   AND    CARBURETTING.  223 

air  supply  enters.  An  auxiliary  air  supply  is  admitted  through 
the  opening  to  the  right,  being  controlled  by  the  valve  B  which  is 
automatic  in  its  action.  The  lift  of  this  valve  may  be  varied  to 
meet  different  requirements,  by  the  adjustable  threaded  spindle. 

Under  operating  conditions  the  pressure  in  the  mixing  chamber 
is  lower  than  that  of  the  atmosphere.  Lowered  pressure  without 
a  correspondingly  lowered  temperature  tends  to  cause  vaporiza- 
tion which  begins  as  soon  as  the  fuel  has  left  the  nozzle.  It  is 
impossible  to  measure  or  estimate  the  extent  of  the  vaporization, 
at  the  nozzle  or  through  the  manifold,  due  to  this  pressure  reduc- 
tion, but  it  is  known  to  be  very  appreciable  in  its  effect.  It  should 
be  considered  as  a  condition  affecting  vaporization,  at  the  nozzle 
end  but  slightly,  but  to  a  much  greater  extent  after  the  fuel  has 
become  suspended  in  the  air. 

The  nozzle  of  average  performance  will,  at  medium  demands, 
deliver  a  thin  conical  sheet  of  liquid.  This  liquid  cone  is  torn 
away  at  its  edge  and  carried  on  by  the  air  column.  Some  of  the 
fuel  torn  away  is  in  small  enough  particles  to  be  considered  as 
spray  or  mist,  and  may  be  taken  as  contributing  directly  to  the 
vapor  content  of  the  mixture ;  but  the  greater  part  sooner  or  later 
strikes  some  part  of  the  containing  walls,  and  later  it  is  picked 
up  in  the  form  of  globules.  These  globules  are  continually  picked 
up  and  thrown  out  by  the  air  stream  in  its  progress  to  the  cylin- 
ders, until  some  of  them  are  sufficiently  small  to  become  per- 
manently entrained  or  have  been  completely  vaporized. 

Bends  in  the  manifold  passages  aggravate  the  expulsion  of  the 
liquid  globules,  but  they  also  permit  of  fuel  once  thrown  out  being 
readily  picked  up  again. 

The  heavier  globules  after  being  thrown  out  at  the  turns  are 
again  picked  up  by  a  following  portion  of  the  air  column.  This 
action  is  repeated  at  each  of  the  turns. 

The  Mixture. — At  first  it  was  thought  that  the  best  carburetter 
was  one  that  gave  a  constant  mixture  under  all  conditions,  it  being 
at  that  time  presumed  that  the  Krebs  carburetter  as  shown  in 


224  SELF-PROPELLED    VEHICLES. 

fig.  169,  gave  this  result.  However,  from  experience  and 
numerous  experiments  it  has  since  been  conceded  that  a  constant 
mixture  is  not  advisable  from  either  the  standpoint  of  fuel 
economy  or  best  operation.  Inasmuch  as  ignition  conditions  vary 
with  the  speed  of  the  engine  and  the  compression  values  vary 
similarly  with  the  throttle  opening,  it  follows  that  the  mixture 
necessary  for  maximum  power  at  any  given  speed  differs  in 
accordance  with  the  immediate  conditions  of  combustion. 

At  low  speeds  the  mixture  should  be  richer  than  at  high.  This 
is  due  to  the  fact  that  at  low  speeds  more  heat  is  lost  to  the  cylin- 
der walls,  more  compression  is  lost  by  leakage,  and  the  combustion 
can  therefore  be  slower,  thus  sustaining  the  pressure.  At  high 
speeds  the  compression  is  higher,  due  to  less  leakage  and  less  loss 
of  heat.  Therefore,  unless  the  mixture  be  leaner  at  high  speed 
there  might  be  danger  of  pre-ignition.* 

A  lean  and  highly  compressed  charge  also  burns  faster  and 
hence  gives  better  pressures  and  fuel  economy  than  a  richer  one. 

The  quantity  of  mixture  that  an  engine  will  take  varies  greatly 
with  the  speed.  At  slow  speeds  the  volume  at  approximately 
carburetter  pressure  is  equal  to  the  cubic  content  of  the  cylinders 
multiplied  by  the  number  of  power  strokes.  At  high  speeds  of 
one  thousand  revolutions  and  over  the  quantity  may  drop  to  less 
than  one-half  the  theoretical  amount,  depending  on  the  design  of 
the  valves,  inlet  piping  and  carburetter  passages.  This  peculiarity 
reacts  upon  the  compression,  and  hence  on  the  mixture  desired 
for  best  results.  It  will  thus  be  seen  that  the  design  of  the  en- 
gine has  a  bearing  on  the  carburetter  design,  which  explains  the 
well  known  but  seemingly  mysterious  fact  that  a  carburetter  giv- 
ing good  results  on  one  engine  sometimes  fails  to  maintain  its 
reputation  when  applied  to  one  of  different  design. 

The  design  and  class  of  ignition  used  have  also  a  marked  in- 
fluence. Poorer  mixtures  can  be  used,  as  the  spark  is  hotter,  the 
throttle  can  be  more  nearly  closed,  resulting  in  increased  engine 
capacity  and  fuel  economy. 

*The  prefix  "pro"  before  Ignition  means  that  the  tuel  charge  is  Ignited  before  the 
time  of  the  spark  and  has  no  connection  with  the  stroke  or  crank  position  as  distin- 
gnished  from  its  usage  when  speaking  of  steam  motors :  for  example,  pre-admission 
means  that  steam  is  admitted  to  the  cylinder  before  the  beginning  of  the  s**oke. 


CARBURETTERS   AND    CARBURETTING. 


225 


To  get  the  maximum  power  out  of  a  given  sized  engine  the  fuel 
should  be  introduced  into  the  cylinders  as  cold  as  possible  con- 
sistent with  complete  evaporation,  intimacy  of  mixture  and  com- 
pleteness of  combustion. 

The  ever  varying  density  and  compositions  of  the  fuels  used 
and  obtainable  introduce  many  complications  into  the  problem. 
These  differences  demand  different  sizes  of  nozzles,  different  float 
levels,  different  amounts  of  heat  to  be  supplied,  and  different  pro- 
portions of  air  for  combustion. 


FIG.  162.— The  Schebler  Carburetter.  A  compensating  air  valve  A,  adjustable  by  the 
screw  M  and  spring  O,  controls  the  air  supply  to  the  mixing  chamber  C.  Above 
this  valve  is  a  shutter  which  may  be  partially  closed  when  cranking  to  increase 
the  suction  in  order  to  obtain  a  rich  mixture.  The  spray  nozzle  is  located  at  D  and 
the  supply  regulated  by  the  needle  valve  E  by  means  of  thumb  wheel  L.  The 
needle  valve  has  two  adjustments,  one  for  high  speed  and  one  for  low.  At  R  is 
the  eccentric  high  speed  adjustment.  Throttle  valve  K  is  of  the  butterfly  type 
and  is  operated  by  the  lever  P.  Heating  is  secured  by  a  jacket  surrounding  the 
throttle.  Gasoline  enters  the  float  chamber  B  through  the  elbow  connection  G.  The 
fuel  level  is  maintained  by  the  concentric  float  F  which  regulates  the  supply  by 
the  inlet  valve  H  and  lever  connection  J.  The  float  point  is  adjustable  by  the 
needle  valve  adjusting  screw  I,  accessible  by  removing  cap  U.  The  carburetter 
is  primed  by  the  tickler  or  flushing  pin  V. 


226 


SHLP-PROPELLED    J 'FJIICLES. 


Owing  to  the  absence  of  a  ready  means  of  ascertaining  the 
quality  of  the  mixture  being  delivered  by  a  carburetter,  the  ma- 
jority of  motors  in  use  are  operating  under  more  or  less  disad- 
vantageous conditions,  even  if  carefully  and  properly  regulated  at 
the  outset. 

Heating  for  Carburetters. — Vaporization  due  to  pressure  re- 
duction is  distinguished  from  vaporization  caused  by  the  sup- 
plying of  heat.  In  the  former  action,  vaporization  can  become 
only  partially  complete,  however  far  the  process  of  reduction  is 


FIG.  163. — A  Jacketed  Carburetter.  The  mixing  chamber  is  shown  surrounded  by  a 
jacket  P,  for  heating  the  mixture.  This  is  accomplished  either  by  connection  with 
the  cooling  water,  or  exhaust  from  engine.  During  the  summer  season,  when  the 
atmospheric  temperature  Is  high,  the  heating  arrangement  may  be  dispensed  with. 

carried,  since  the  part  of  the  liquid  which  vaporizes  does  so 
through  the  abstraction  of  heat  from  the  remainder,  which  be- 
comes constantly  colder.  Vaporization  due  to  pressure  reduc- 
tion by  engine  suction  will  continue  until  the  temperature  of  the 
liquid  becomes  so  low  that  vaporization  ceases  until  heat  is  sup- 
plied from  some  outside  source. 

Where  vaporization  is  brought  about  entirely  by  heat  from 
some  outside  source  the  degree  to  which  it  may  be  carried  de- 


CARBURETTERS   AND    CARBURETTING.  227 

pends  wholly  upon  the  amount  of  heat  supplied,  since  the  tem- 
perature of  the  liquid  is  being  constantly  raised  to  or  maintained 
at  the  proper  point. 

When  a  carburetter  is  rather  small,  for  the  engine  which  it  has 
to  supply,  it  becomes  very  cold  while  in  operation,  as  the  amount 
of  heat  necessary  to  effect  the  evaporation  of  the  gasoline  is  more 
than  is  available  from  the  entering  air  or  than  could  be  secured 
through  the  metal  of  the  carburetter  by  conduction.  The  tem- 
perature of  the  metal  becomes  so  low  that  water  condenses  on  it, 
and,  in  extreme  cases,  is  deported  in  the  form  of  frost.  This  in- 
dicates a  temperature  within  the  carburetter  too  low  for  the  suc- 
cessful use  of  inferior  fuel,  and  so  low  as  to  possibly  affect  the 
intimacy  of  the  resulting  mixture  even  if  high  test  gasoline  be 
used.  Moreover,  if  any  water  be  present  in  the  float  chamber,  it 
will  be  likely  to  freeze  and  disturb  the  flow  of  the  gasoline. 

These  several  undesirable  results  are  produced  by  the  use  of  a 
carburetter  too  small  for  the  engine.  To  meet  these  conditions, 
some  makers  provide  means  for  heating  the  air  supply.  This 
may  be  accomplished  by  arranging  the  outside  end  of  the  air  inlet 
pipe  so  as  to  terminate  closely  to  the  exhaust  manifold  or  some 
hot  portion  of  the  engine.  Not  enough  attention  has  been  paid 
to  jacketing  carburetters  to  replenish  the  heat  taken  up  by  the 
evaporation  of  the  fuel,  and,  judging  from  observation  of  car- 
buretters now  in  use,  it  seems  that  very  few  engineers  have  taken 
the  trouble  to  look  into  the  probable  economics  that  might  be  ef- 
fected by  proper  jacketing.  It  appears,  from  the  results  of  ex- 
periments that  the  fuel  consumption  decreases  with  an  increase  ot 
jacket  temperature  for  a  given  output,  but  only  up  to  a  certain 
point.  The  most  effective  temperature  seems  to  be  about  no0 
Fahr. 

Besides  heating  the  air,  carburetters  are  sometimes  jacketed  as 
shown  in  fig.  163,  and  the  heat  supplied  to  the  jacket  by  two 
methods.  One  is  by  means  of  hot  water,  taken  from  the  cooling 
system  by  the  use  of  a  shunt,  and  the  other  by  the  exhaust  gases. 
Heating  the  carburetter  by  cooling  water  gives  good  results,  but 


228 


SELF-PROPELLED   VEHICLES. 


the  starting  of  the  motor  is  more  difficult,  especially  in  winter. 
Heating  the  carburetters  by  exhaust  gases  is  open  to  some  objec- 
tion, as  oil  and  carbon  soot  are  deposited  in  the  heating  jacket. 

Surface  or  "Puddle"  Carburetters. — In  this  method  of  car- 
buretting,  a  thin  layer  of  air  is  passed  over  the  surface  of  the 
liquid.  The  surface  carburetter  consists  of  a  U-shaped  mixing 
chamber,  in  the  base  of  which  a  puddle  of  gasoline  about  y$  inch 
deep  is  maintained  by  float  feed  as  shown  in  fig.  164.  As  this 
puddle  is  supplied  by  gravity,  a  weaker  suction  will  produce  a 
mixture,  than  where  the  gasoline  must  be  both  lifted  and  sprayed 
by  suction.  This  type  of  carburetter  is  quite  sensitive  to  changes, 
both  in  the  float  level  and  in  the  needle  valve  adjustment. 


FIG.  164.— The  surface  or  "puddle"  type  of  carburetter.  Air  flows  through  the  U 
shaped  tube  or  mixing  chamber  as  indicated  by  the  arrows.  The  small  puddle  of 
gasoline  in  the  bottom  of  the  mixing  chamber  is  mixed  with  the  air  by  surface 
contact.  The  size  or  cross  section  of  tin;  mixing  chamber  is  usually  reduced  at 
the  region  of  the  puddle  so  as  to  Increase  the  velocity  of  the  inflowing  air.  The 
gasoline  level  in  the  float  chamber  is  maintained  slightly  higher  than  the  fuel 
Inlet  to  the  mixing  chamber  feeding  the  puddle  by  gravity.  Hence,  no  initial 
suction  is  required  to  cause  a  flow  of  gasoline  into  the  mixing  chamber. 

An  example  of  surface  carburetter  construction  is  shown  in  the 
Holley,  fig.  165.  This  carburetter  has  no  auxiliary  air  inlet  and 
valve.  A  high  air  velocity  is  obtained  in  the  mixing  chamber  by 
applying  the  principle  of  the  venturi  tube. 

Referring  to  the  figure,  which  shows  the  carburetter  in  two  sec- 
tions, it  will  be  seen  that  the  air  enters  at  A  and  passes  downward 


CARBURETTERS   AND    CARBURETTING. 


229 


and  up  through  a  U-shaped  tube,  which  is  constricted  at  its  low- 
est point.  In  the  floor  of  the  U  is  the  gasoline  orifice  B,  which  is 
regulated  by  a  needle  valve  E.  The  mixture  passes  through  a 
butterfly  throttle  valve  and  on  to  the  engine  by  the  connection  C. 
The  float  chamber  surrounds  the  lowest  part  of  the  U,  and  has 
an  annular  cork  float  J,  which  controls  the  gasoline  valve  L 
through  a  lever  N  pivoted  at  K.  The  U-shaped  mixing  chamber 
is  merely  the  venturi  tube  in  a  special  form,  allowing  a  very  high 
air  velocity  to  be  obtained  at  B. 

When  the  engine  is  at  rest  there  is  a  puddle  of  gasoline  about 
Y%  inch  deep  in  the  bottom  of  the  mixing  chamber.    Consequently 


Fio.  165.— The  Holley  Carburetter.  This  Is  an  example  of  the  surface  or  "puddle** 
type.  The  fuel  level  is  maintained  slightly  higher  than  the  inlet  orifice  which 
causes  a  small  "  puddle  "  of  gasoline  to  form  in  tho  bottom  of  the  U  shaped  mixing 
chamber.  The  operation  of  this  carburetter  is  described  in  detail  in  the  text. 

when  the  motor  is  starting  or  running  very  slowly  the  air  does 
not  have  to  lift  the  gasoline  at  all  but  simply  draws  over  the  pud- 
dle and  is  carburetted  by  surface  evaporation.  As  the  throttle 
is  opened  and  the  air  velocity  increases  the  puddle  is  gradually 
swept  away  by  the  strong  air  current  passing  over  it ;  at  the  higher 
speeds  the  puddle  is  wiped  out  entirely  .and  a  spray  of  the  ordinary 
sort  takes  its  place. 


230  SELF-PROPELLED    VEHICLES. 

In  starting  the  engine  the  float  is  depressed  by  the  primer  H 
and  to  prevent  the  mixing  chamber  from  being  flooded  to  excess 
a  drain  pipe  D  is  provided. 

The  throttle  valve  is  operated  by  the  lever  F,  and  the  adjusta- 
ble stop  screw  G  permits  regulation  of  the  opening  for  minimum 
speed.  The  adjustment  is  through  the  needle  valve  E.  A  dash- 
board connection  is  sometimes  provided  to  regulate  the  opening 
of  this  valve. 

When  there  is  a  dashboard  connection  the  upper  end  of  the 
needle  valve  stem  has  a  universal  joint,  from  which  a  rod  extends 
through  the  dashboard  to  a  dial  and  regulating  needle  as  shown 
in  fig:.  1 66. 


Fro.  166. — A  Surface  Carburetter,  arranged  for  dashboard  control  of  fuel  needle  valve. 
A  universal  joint  is  fitted  to  the  valve  stem,  having  an  extension  connecting  with 
the  graduated  dial,  shown  at  the  right. 

A  spring  ratchet  holds  the  dial  where  set,  and  a  hinge  permits 
it  to  accommodate  itself  to  the  angle  of  the  rod.  This  attachment 
enables  the  user  to  adjust  the  carburetter  under  running  condi- 
tions, a  matter  of  an  instant,  whereas  otherwise  he  might  experi- 
ment repeatedly.  It  also  makes  it  possible  to  adjust  for  day  to 
day  variations  in  humidity,  temperature,  and  grade  of  fuel,  as  well 
as  to  start  on  a  rich  mixture  and  cut  down  when  the  engine  is 
warmed  up.  A  special  adjustment  for  hills  and  sand  is  also  pos- 
sible. 

Venturi  Carburetters. — When  any  fluid  passes  through  a  pipe 
of  variable  cross  section  or  size,  the  quantity  passing  any  given 


CARBURETTERS   AND    CARBURETTING. 


231 


section  in  a  given  time  is  the  same ;  such  being  the  case,  the 
velocity  of  the  fluid  in  the  various  sections  is  inversely  propor- 
tional to  the  areas  of  the  sections.  Hence  it  is  evident,  from  the 
foregoing  facts,  that  the  pressure  is  greatest  at  the  largest  sec- 
tion and  least  at  the  smallest. 

This  is  known  as  the  "venturi  principle"  and  has  been  utilized  in  the 
design  of  some  makes  of  carburetters  with  good  results.  In  applying  this 
principle  to  carburetter  design,  the  mixing  chamber  is  shaped  like  two 


FIG.  3tfT.  -The  Kingston  Carburetter.  An  example  of  the  venturi  type  of 
cs.i  buretter.  Air  enters  at  A  and  converges  above  the  nozzle  N  in  the 
rastricted  passage  which  produces  the  venturi  tube  effect.  D  is  the 
exit  to  the  motor  controlled  by  the  butterfly  throttle  E.  Auxiliary 
air  enters  through  five  circular  openings  G,  arranged  in  a  semi-circle 
in  the  floor  of  an  extension  H  of  the  mixing  chamber.  Each  of  these 
five  openings  consist  of  a  bushing  K  threaded  into  the  opening  in  the 
expansion  H,  and  having  its  top  beveled  to  receive  a  %-inch  bell 
metal  bronze  ball  L,  which  is  retained  in  position  by  a  threaded  bush- 
ing M,  fitting  in  the  top  of  the  extension  H.  Gasoline  enters  from 
the  tank  through  J,  controlled  by  needle  valve  R.  operated  through 
lever  S.  Complete  control  of  the  nozzle  N  is  through  the  needle  valve 
V,  which  at  the  top  of  the  carburetter  has  a  T-piece  X,  by  which  it 
can  be  raised  or  lowered,  thereby  regulating  the  flow  of  gasoline. 
A  serrated  hub  W  of  the  throttle,  permits  the  handle  W  to  be  turned 
in  any  direction  convenient  for  the  motor  by  loosening  locknut  Z. 
Similarly,  the  intake  pipe  A,  which  is  a  separate  casting,  can  be 
turned  to  any  desired  position  by  loosening  the  nut  A'. 

hollow  truncated  cones  with  their  small  ends  brought  together,  or  in  other 
words  like  the  familiar  hour  glass.  By  locating  the  spray  nozzle  at  the 
point  of  least  cross  section,  the  conditions  are  favorable,  for  securing  that 


232  SELF-PROPELLED    VEHICLES. 

marked  economy  of  fuel  which  results  from  the  use  of  high  air  velocities 
under  low  pressures.  The  greater  the  pressure  drop  at  the  nozzle,  accom- 
panied by  a  proportional  increase  in  the  air  velocity,  the  better  will  be  the 
fuel  division  and  vaporization 

The  very  rapid  agitation  and  internal  motion  of  the  mixture  column,  due 
to  the  restricted  section  of  the  venturi  tube,  tends  to  produce  a 
homogeneous  fuel  charge.  A  lowering  of  the  pressure,  lowers  the  tem- 
perature of  the  liquid  through  vaporization,  hence,  in  venturi  carburetters 
where  any  marked  venturi  effect  is  sought,  jacketing  is  advisable. 

The  advantages  of  the  venturi  tube  as  applied  to  carburetters  may  be 
summed  up  as  follows :  Homogeneity  of  mixture ;  ease  with  which  the 
mixing  chamber  may  be  jacketed,  either  by  air  or  water;  the  mixing  cham- 
ber may  be  placed  in  any  plane,  thus  adapting  it  to  varied  motor  designs. 

Selecting  a  Carburetter. — -Automobile  owners  often  seek  to 
improve  the  efficiency  and  increase  the  power  of  their  motors  by 
the  fitting  of  new  carburetters.  On  account  of  this,  it  is  well  to 
point  out  certain  truths  which  may  be  of  service.  Before  select- 
ing a  carburetter,  the  buyer  should  have  as  clear  an  understand- 
ing of  its  principles  as  possible.  The  ideal  carburetter  require- 
ments are  as  follows: 

1.  It  must  intimately  mix  in  proper  proportions   the  mixture   to   suit 
varying  engine  speeds. 

2.  If  of  the  spray  type,  the  air  velocity  at  the  nozzle  should  be  great 
enough   at   slowest  engine   speeds   to   overcome   the   initial   lift  necessary 
to  bring  the  fuel  to  the  nozzle  level  and  draw  it  into  the  mixing  chamber. 

3.  The  nozzle  should  be  accessible  for  cleaning  and  should  be  so  shaped, 
together  with  the  needle  valve  that  it  will  deliver  gasoline  in  a  very  finely 
divided  form. 

4.  The  float  chamber  should  be  concentric  with  the  nozzle,  so  that  the 
fuel  level  at  that  point  will  not  be  disturbed  by  any  inclination  of  the  car. 

5.  A  gauze  strainer  should  be  provided  at  the  gasoline  inlet  and  also 
another  at  the  air  inlet. 

6.  The  fuel  should  flow  in  a  single  direction  either  up  or  down  through 
the  float  chamber  so  no  pockets  will  exist. 

7.  There  should  be  a  vent  in  the  top  of  the  float  chamber. 

8.  The  float  point  should  be  easily  ground  and  moved  by  the  motion  of 
the  float. 

9.  The  float  should  be  adjustable  to  different  grades  of  fuel. 


CARBURETTERS  AND    CARBURETTING. 


233 


10.  The   passage   between    the   float   and   mixing   chambers    should   be 
large  to  prevent  clogging. 

11.  The  air  passage  should  be  contracted  at  the  nozzle. 

12.  A  removable  gauze  should  be  inserted  in  the  mixing  chamber  to 
prevent  unsprayed  liquid  reaching  the  engine. 

13.  The   gasoline   inlet   valve   should   be   arranged   to   have  dashboard 
control. 

14.  There  should  be  means  of  heating  in  cold  weather  or  with  low  gravity 
fuels. 


FIG.  168.— The  "Wlllet  Carburetter.  This  consists  of  two  carburetters  In  one,  each  with 
Its  own  spray  nozzle  and  adjustment.  The  small  carburetter  B  is  used  for  low  speeds, 
and  a  second  one  C,  cutting  in  on  moderate  and  high  speeds.  Automatic  action  is 
secured  hy  the  spring  operated  valve  F.  The  air  supply  of  carburetter  B  may  be 
regulated  by  valve  D,  having  dashboard  control.  Closing  this  valve  produces  a 
strong  suction  on  the  spray  nozzle  in  B,  thus  drawing  a  rich  mixture  to  make  easy 
starting  possible.  The  valve  is  then  opened  to  its  normal  position,  which  is  wide 
open.  Should  the  weather  be  cold  and  a  richer  mixture  required,  this  valve  may 
be  closed  somewhat.  The  entire  carburetter  is  controlled  by  the  butterfly  throttle 
valve  A.  Nozzle  H  has  a  single  opening  while  G  is  a  multi-nozzle  having  four  out- 
lets. Both  mixing  chambers  may  be  heated  by  the  jacket  Y,.  The  fuel  flow  to 
nozzle  is  controlled  by  the  needle  valves  I, 


SHIP-PROPELLED   VEHICLES. 


Size  of  Carburetter. — In  selecting  a  carburetter  the  first  thing 
to  be  determined  is  the  proper  size  as  success  or  failure  in  operat- 
ing the  car  depends  upon  it.  If  too  large  there  would  be  difficulty 
in  starting  and  it  would  be  necessary  to  feed  more  fuel  than  would 
otherwise  be  required,  because  the  air  velocity  through  the  mixing 


Flo.  189.— The  Krebs  Carburetter,  used  on  the  Panhard-Levasaor  motors. 
Gasoline  comes  from  the  float  chamber  through  channel  P  to  the 
spray  nozzle  L,  air  being  admitted  at  K.  Q  is  the  mixing  chamber; 
the  mixture  passes  into  the  feed  tube  M  through  the  port  H,  whose 
opening  is  controlled  by  the  position  of  the  serrated  perforations  in 
piston  O,  moving  through  bore  R,  as  controlled  by  the  governor 
through  piston  rod  S.  When  more  air  than  the  fixed  quantity  ad- 
mitted at  K  is  required,  the  excess  motor  suction  depresses  the  small 
piston  A,  held  in  cylinder  F,  by  the  spring  E,  and  sliding  in  the 
elastic  diaphragm  C.  Air  Is  admitted  above  it  through  a  small  port 
at  B.  The  depression  of  piston  A,  causes  the  slide  H,  to  move  down- 
ward in  tube  G,  thus  opening  the  ports  I  and  J,  admitting  the  re- 
quired amount  of  air. 

chamber  would  be  too  low  to  cause  an  intimate  mixing  of  the  fuel 
spray  with  the  air.  Moreover,  a  very  rapid  cranking  on  starting 
would  be  necessary  in  order  to  produce  sufficient  suction  in  the 
mixing  chamber  to  draw  gasoline  through  the  nozzle.* 


*  It  must  be  remembered,  that  in  nearly  all  carburetters  the  level  of  the  gasoline  in 
the  float  chamber  being  somewhat  lower  than  the  nozzle,  an  "  initial  suction  "  is  neces- 
sary to  get  the  liquid  to  the  point  of  discharge  and  an  additional  suction  to  discharge  it 
into  the  mixing  chamber. 


CARBURETTERS  AND    CARBURETTING.  235 

The  carburetter  size  should  be  determined  by  the  area  of  the 
valve  opening  on  the  engine  and  not  by  the  cylinder  displacement 
as  the  former  is  a  true  measure  of  the  engine  capacity.  A  car- 
buretter cannot  deliver  more  charge  to  a  cylinder  than  the  area  of 
the  valve  opening  will  allow  to  pass.  Hence,  a  large  carburetter 
with  excess  passage  area  cannot  cause  an  engine  to  deliver  more 
power  than  it  would  with  one  having  a  passage  equal  in  area  to 
that  of  the  valve  opening. 

A  carburetter  too  large  would  not  only  waste  fuel  but  reduce 
the  power  of  the  engine  by  furnishing  a  weak  and  non-homogeneous 
mixture.  On  the  other  hand  it  is  obvious  that  if  the  carburetter 
be  too  small  the  engine  would  not  develop  its  rated  power,  as  it 
could  not  deliver  a  full  charge  at  high  speed.  From  the  forego- 
ing it  follows  that  the  carburetter  of  proper  size  should  have  its 
passage  area  equal  to  the  valve  opening  of  the  engine.*  In  multi- 
cylinder  engines  this  area  is  equal  to  the  valve  opening  multiplied 
by  the  number  of  suction  strokes  which  take  place  simultaneously, 
determined  from  the  sequence  of  cranks,  as  explained  in  plate  III. 

To  find  the  valve  opening  area,  remove  an  intake  valve  and  measure  the 
diameter  of  the  port  it  covers,  and  also  the  lift  of  the  valve  and  angle  of 
valve  seat.  The  effective  valve  opening  area  is  equal  to  the  slant  surface 
of  the  frustrum  of  a  cone  whose  upper  base  diameter  is  equal  to  the  port 
diameter,  whose  slant  height  is  equal  to  the  lift  of  valve  times  the  sine 
of  the  angle  of  the  valve  seat  and  whose  lower  base  diameter  is  equal  to 
the  port  diameter  plus  twice  the  valve  lift  times  cos  <2>  sin  <P. 

The  above  values  substituted  in  the  following  formula  will  give  the  re- 
quired area. 

Area  valve  opening  =  \  slant  height  X  (circumference  of  upper  base  + 
circumference  of  lower  base). 

This  area  is  to  be  multiplied  by  the  number  of  suction  strokes  occurring 
at  one  time.  A  carburetter  having  this  area  will  be  of  the  correct  size 
provided  the  main  and  auxiliary  passages  through  the  carburetter  are 
smooth  surfaced,  and  as  direct  as  possible.  If  it  be  made  up  of  tortuous 
rough  passages,  sharp  bends,  etc.,  a  little  excess  area  should  be  provided 
to  compensate  for  the  increased  frictional  resistance  resulting  therefrom. 

*  In  the  exact  determination  of  carburetter  size,  sufficient  excess  passage  area  must 
be  provided  to  correct  for  the  friction  of  the  mixture  through  the  carburetter  and 
inlet  manifold.  It  is  not  probable  that  a  carburetter  could  be  found  having  exactly 
the  same  size  outlet  as  the  valve  opening,  hence,  the  nearest  size  larger  is  selected  whicn 
will  be  amply  large  to  allow  for  friction.  The  inlet  manifold,  of  course,  must  be  of  the 
exact  size  to  correspond  with  the  carburetter. 


236 


SELF-PROPELLED   VEHICLES. 


Having  determined  the  required  area,  a  carburetter  may  be  se- 
lected having  its  outlet  diameter  corresponding  as  near  as  possible 
to  this  area — taking  the  nearest  larger  size.  Carburetter  makers 
proportion  the  outlet  to  correspond  to  standard  pipe  sizes,  as  given 
in  the  table,  but  it  should  be  noted  that  internal  pipe  diameters  do 
not  correspond  to  the  nominal  diameters  as  listed.  For  instance,  a 
pipe  listed  as  3^  inch  has  an  internal  diameter  of  .82  inch,  hence, 
the  correct  pipe  size  should  be  obtained  from  the  table. 

TABLE    OP    STANDARD     PIPE    SIZES. 


NOMINAL 
INSIDB 

ACTUAI, 

OUTSIDE 

ACTUAI, 
INSIDE 

INTERNAL 
AREA. 

DIAMETER. 

DIAMETER. 

DIAMETER. 

ins. 

ins. 

ins. 

sq.  ins. 

/4 

.840 

.622 

•304 

$ 

1.050 

.824 

•533 

l 

1-315 

1.048 

.861 

i% 

i.  660 

1.380 

1.496 

iH 

1.900 

1.610 

2.036 

9 

2-375 

2.067 

3-356 

2^ 

2-875 

2.468 

4.780 

3 

3-500 

3.067 

7-383 

3X 

4.000 

3-548 

9.887 

4 

4-500 

4.026 

12.730 

Adjusting  the  Carburetter. — It  is  difficult  to  state  a  method 
which  will  apply  to  the  adjustment  of  all  makes  of  carburetters, 
but  it  is  possible  to  give  a  few  general  instructions. 

1.  The  interior  of  the  float  chamber  should  be  examined  with 
a  view  to  removing  any  dirt  or  other  matter  which  might  inter- 
fere with  the  proper  flow  of  the  gasoline. 

2.  With  a  spray  carburetter,  it  is  sometimes  necessary  to  ob- 
tain by  priming  a  mixture  for  starting.     It  is,  however,  possible 
in  doing  this  to  make  too  lean  or  too  rich  a  mixture ;  and  if  the 
adjustments  be  decidedly  wrong,  the  mixture  formed  on  the  first 
few  revolutions  will  be  so  bad  that  the  engine  will  stop. 

3.  Sometimes  the  float  is  too  high  or  too  low,  and  the  gasoline 
overflows  the  spray  nozzle  continually,  or  is  so  low  that  a  con- 


CARBURETTERS   AND    CARBURETTING. 


237 


siderable  suction  is  required.  Now  as  before  stated,  the  gasoline 
level  should  be  such  that  the  liquid  will  form  a  bubble  at  the  noz- 
zle to  be  blown  off  at  will.  The  exact  height  should  be  found  by 
this  method. 

4.  After  the  float  chamber  has  had  time  to  fill,  observe  whether 
gasoline  drips  from  the  nozzle.  If  it  does,  the  float  valve  should 
be  investigated.  If  pressing  it  shut,  stops  the  dripping,  the  float 
is  too  high ;  if  the  dripping  persist,  the  valve  leaks  and  needs  to 
be  reground.  Occasionally  a  float  and  float  valve  are  so  arranged 
that  the  valve,  although  tight  in  one  position,  may  slant  over  a 
trifle  and  leak  from  that  cause. 


Fio.  170.— The  Petrie  Carburetter.  An  air  valve  A  is  provided  which  completely 
closes  the  air  port  when  not  in  operation  and  also  a  gasoline  valve  J  which  com- 
pletely closes  the  gasoline  port  at  the  same  time.  The  action  of  the  air  valve  is  re- 
sisted by  a  long  spring  B.  The  gasoline  valve  is  lifted  from  its  seat  by  the  action 
of  the  air  valve  through  the  lever  G  and  the  lifter  K.  It  will  be  noticed  that  the  ful- 
crum M  of  the  lever  G,  the  point  at  which  the  lever  G  rests  upon  the  air  valve  A,  and 
the  point  at  which  the  lifter  K  rests  on  the  lever  G  are  in  a  straight  line,  giving  a 
lift  to  the  gasoline  valve  J  in  proportion  to  the  lift  of  the  air  valve.  To  change  the 
proportion  between  the  gasoline  and  air  openings  a  regulating  cap  H  is  provided, 
by  means  of  which  the  position  of  the  point  L,  at  which  the  lifter  K  rests  upon  the 
lever  G,  may  be  varied  at  will,  thus  varying  the  lift  of  the  gasoline  valve.  The  air 
valve  is  provided  with  a  glycerine  dashpot  E  to  make  the  operation  noiseless.  The 
valve  stem  C  extends  into  the  dash  pot  terminating  in  the  piston  D,  held  in  tension 
by  the  spring  B.  The  mixture  to  engine  is  controlled  by  the  throttle  F.  To  the 
left  is  shown  a  section  of  the  float  chamber  with  needle  valve  Q  arranged  concen- 
tric to  float. 


238 


SELF-PROPELLED    VEHICLES. 


If  no  dripping  occur  after  standing,  depress  the  float,  and  on 
the  first  sign  of  dripping  crank  the  engine.  If  it  does  not  start, 
prime  the  carburetter  again.  In  case  this  fails,  shut  off  the  gaso- 
line at  the  tank,  and  if  there  be  a  drainage  outlet  from  the  float 
chamber  draw  off  a  couple  of  teaspoonsful  of  gasoline.  This 
weakens  the  mixture.  Repeated  cautious  experimenting  in  this 
manner  will  soon  establish  the  priming  required  to  start  the  engine 
when  cold. 

5.  Gasoline  when  warm  evaporates  more  rapidly,  and  caution  Is 
required  not  to  prime  too  much.  Many  carburetters  with  a  small 
primary  air  passage  will  start  the  engine  without  priming,  once 
they  are  properly  adjusted. 


Fio.  171.— A  few  examples  of  carburetter  design,  showing  courses  followed  by  the 
fuel  after  leaving  the  nozzle,  for  different  arrangements  of  parts  and  passages. 
The  heavy  arrowed  line  leading  from  the  nozzle  X  indicates  the  course  taken  by 
the  mixture  as  influenced  by  the  design.  These  diagrams  are  self  explanatory, 
and  show  that  liquid  globules  are  precipitated  against  some  portions  of  the 
mixing  chamber  wall  almost  immediately  after  leaving  the  nozzle.  This  tends 
to  disturb  the  homogeneity  of  the  mixture,  and  requires  that  provisions  be  made 
for  correcting  this  effect  in  the  remaining  portions  of  the  passage. 

If  the  engine  should  start,  but  immediately  die  down,  try  de- 
pressing the  float.  If  the  cause  of  dying  down  be  too  weak  a  mix- 
ture, this  will  keep  the  engine  going. 

6.  When  there  is  an  auxiliary  spring  controlled  air  valve,  tighten 
the  spring  sufficiently  to  hold  it  on  its  seat  at  low  engine  speeds 
and  throttle  openings.  With  the  engine  running  light  at  about 
250  to  300  revolutions  per  minute,  adjust  the  fuel  needle  valve  to 
such  a  position  that,  with  the  spark  just  back  of  center,  the  speed 
can  be  cut  down  to  below  200  revolutions  per  minute  without  mis- 
firing. 


CARBURETTERS   AND    CARBURETT1NG. 


239 


7.  Having  made  this  adjustment,  retard  the  spark  fully  and 
with  clutch  still  disengaged,  slightly  open  the  throttle.  The  engine 
should  attain  at  least  its  maximum  road  speed  with  the  throttle 
about  one-eighth  open.     The  auxiliary  air  valve  should  begin  to 
open  at  about  250  r.  p.  m.,  but  should  not  open  fully  for  maximum 
speed  with  engine  running  light,  as  it  is  not  taking  full  charges. 

8.  Adjust  the  spring  of  the  auxiliary  valve  so  that  it  only  par- 
tially opens  for  maximum  speed.     All  the  above  adjustments  are 
to  be  made  with  the  clutch  disengaged. 

9.  Now  try  the  car  on  the  road  at  moderate  speeds.     Suppose 
the  engine  runs  in  a  sluggish  manner,  vary  the  gasoline  supply 
without  stopping:  first  reduce,  then  increase  the  richness  of  the 


FIG.  172.— Several  designs  of  throttle  valves  are  here  shown  in  a  partially  open  posi- 
tion, where  the  effects  of  separation  and  deflection  of  the  liquid  globules  are 
illustrated  for  each  case.  It  will  be  seen  that  all  these  throttles  act  as  separators 
when  not  fully  open.  The  first  four  throw  the  liquid  upon  the  walls  unevenly. 
The  last  one  shown  to  the  right,  while  better  distributing  the  liquid  over  the 
walls,  is  like  the  rest,  an  energetic  separator.  Throttles  like  number  four  are 
rarely  found  in  later  designs.  Probably  all  who  have  had  any  experience  with 
this  type  of  throttle  remember  that  a  drain  cock  is  inserted  at  A. 

mixture  and  note  the  affect  on  the  car's  performance  on  level 
ground.  A  few  trials  should  give  a  mixture  on  which  the  car 
will  run  well;  the  operation  thus  obtained,  does  not  prove  alto- 
gether that  the  mixture  is  correct  as  the  car  may  be  running  with 
more  throttle  opening  than  is  necessary. 

10.  If  the  radiator  should  heat  up  on  level  ground  and  over 
heats  on  hills,  it  indicates  too  rich  a  mixture ;  correct  this  by  ad- 
justing the  auxiliary  air  valve.  A  change  in  spring  tension  has  a 
greater  proportional  effect  at  low  than  at  high  speeds. 

Note  whether  the  valve  strikes  the  stop  at  moderate  speed.    If 


240  SELF-PROPELLED    VEHICLES. 

it  does,  it  will  not  admit  sufficient  air  at  high  speed,  hence,  ad- 
just the  stop,  if  possible,  so  the  valve  may  open  further.  If  it 
should  flutter  at  high  speed,  the  lift  must  be  reduced  to  increase 
the  spring  tension  and  diminish  the  fuel  supply  to  the  nozzle. 

11.  In  case  there  be  no  needle  valve  controlling  the  spray,  re- 
duce the  primary  air  inlet  so  that  a  larger  proportion  of  the  total 
air  stream  will  go  through  the  auxiliary  valve.     These  changes 
will  weaken  the  mixture  more  at  high  than  at  low  speeds,  as  it 
should  be  for  proper  working. 

12.  If  in  running  the  car  on  level  ground,  the  motor  be  simply 
weak  and  not  accompanied  by  heating  it  indicates  that  the  mix- 
ture is  too  lean.     A  good  test  of  the  mixture  is  the  response  to  the 
spark  advance.     If  the  mixture  be  bad,  the  spark  must  be  ad- 
vanced considerably  to  produce  any  noticeable  acceleration,  where- 
as with  the  correct  mixture  any  change  in  the  advance  is  felt  at 
once,  and  the  maximum  advance  is  not  needed  except  at  maximum 
speeds.     Even  more  marked  is  the  response  to  the  throttle  when 
the  latter  is  nearly  closed. 

13.  Much  depends  upon  the  proper  adjustment  of  the  air  valve 
spring.     To  get  the  best  results  in  power  and  economy,  the  ten- 
sion of  the  spring  should  be  almost  nothing  with  the  valve  upon 
its  seat ;  and,  if  the  primary  air  inlet  and  fuel  valve  be  carefully 
adjusted  as  above,  it  will  be  found  that  no  more  tension  is  needed 
to  maintain  the  valve  in  a  closed  position  while  starting  the  en- 
gine.    The  spring  may  not  be  composed  of  the  proper  size  wire 
nor  have  the  right  number  of  turns  to  give  the  proper  initial  ten- 
sion, but,  before  altering  or  changing  the  spring,  remove  the  ex- 
haust piping  or  manifold  and  observe  the  flame  colors  which  are 
reliable  indications  of  the  quality  of  the  mixture.     The  stiffness  of 
the  spring  should  be  such  that  at  the  lower  and  medium  speeds 
the  color  of  the  flame  will  be  a  dark  blue  verging  upon  violet; 
for  other  speeds  up  to  the  normal  or  rated  speed  of  the  engine, 
the  color  should  be  a  somewhat  lighter  blue,  the  color  gradually 
fading  but  at  no  point  losing  its  decided  blue  tinge. 


CARBURETTERS   AND    CARBURHTTING.  241 

This  fading  of  the  blue  color  denotes  a  gradual  weakening  of 
the  mixture  as  it  should  do  for  increasing  speeds.  One  necessity, 
among  others  before  explained,  for  this  gradual  weakening  of 
the  mixture  is  that  at  high  piston  speeds  a  slightly  weakened 
mixture  burns  faster  than  does  one  of  full  strength.  This  being 
necessary  at  high  speeds  to  secure  complete  combustion  before 
exhaust. 


FIG.  173.— The  B.  G.  v.  B.  Carburetter.  In  this  design  the  chief  features  are :  an  ad. 
justable  primary  air  inlet,  a  jacketed  venturi  tube  mixing  chamber  and  a  triple 
auxiliary  valve.  The  nozzle  H  which  has  no  needle  valve,  is  regulated  for  gasoline 
flow  by  loosening  s?t  nut  J  and  adjusting  the  primary  air  inlet  cone  I.  This  cone 
catches  any  overflow  of  gasoline  in  priming.  The  nozzle  H  may  be  cleaned  by 
removing  screw  plug  K.  In  operation  the  auxiliary  valve  O  opens  first  to  supply 
auxiliarvair,  and  with  increasing  speeds  additional  air  is  admitted  the  opening 
of  N  and  M,  the  three  valves  acting  progressively.  These  valves  are  attached  to 
the  part  P  which  is  removable  for  inspection.  A  butterfly  throttle  is  located  at  F. 
The  float  E  is  arranged  concentric  with  the  inlet  needle  valve  C  and  the  float 
point  has  spring  adjustment,  regulated  by  turning  D  which  is  provided  with  a 
stop,  B.  At  the  upper  end  is  a  priming  lever  A.  The  float  chamber  is  drained  by 
the  cock  L  A  union  S  permits  its  lower  part  T  containing  the  gasoline  connection 
to  be  swung  into  any  position  most  convenient  for  piping  to  tank. 

A  yellow  tint  in  the  exhaust  indicates  too  little  gasoline  in  pn> 
portion  to  the  amount  of  air  supplied  while  red  indicates  too  much 


242  SELF-PROPELLED    VEHICLES. 

gasoline.  Both  these  tints,  yellow  and  red,  show  that  the  engine 
is  not  developing  its  best  power,  moreover  the  red  shows  a  waste 
of  fuel. 

When  it  is  impossible  to  adjust  the  carburetter  so  as  to  get  the  blue  flame 
color,  it  is  usually  due  to  faulty  spraying  action  of  the  nozzle.  This  noz- 
zle defect  is  further  emphasized  by  fluctuations  of  the  flame  color  from 
yellow  to  red  or  vice  versa,  indicating  coarseness  of  fuel  division  and  a 
resulting  non-homogeneous  mixture.  The  nozzle  may  not  be  entirely  at 
fault;  the  mixing  is  somewhat  dependent  upon  the  manner  in  which  the 
carburetted  primary  air  is  brought  into  contact  with  that  from  the  auxil- 
iary port ;  but  whatever  the  whole  cause  of  the  trouble  may  be,  the  nozzle 
is  chiefly  at  fault. 

14.  Sometimes  a  spring  adjusted  to  give  a  proper  mixture  at 
one  speed  will  not  give  good  results  at  other  speeds.  Now,  sup- 
pose the  mixture  were  found  to  be  originally  too  rich  at  high 
speeds,  and  was  corrected  by  slackening  the  spring  or  increasing 
the  auxiliary  valve  lift:  if  the  change  were  only  in  the  lift  the 
mixture  at  lower  speeds  has  probably  not  been  affected.  If,  how- 
ever, the  spring  has  been  slackened,  the  mixture  may  be  too  lean 
at  low  speeds,  owing  to  the  air  valve  opening  too  soon.  One  way 
to  correct  this  would  be  to  use  a  spring  having  a  larger  number 
of  turns,  but  a  satisfactory  result  may  usually  be  reached  by  in- 
creasing the  spring  tension  and  reducing  the  spray  orifice. 

It  is  quite  difficult  to  make  adjustments  on  the  road  owing  to  the  mo- 
tion of  the  car  and  the  inaccessible  position  of  the  carburetter,  hence,  if  the 
running  load  be  applied  to  the  engine  with  the  car  standing,  these  adjust- 
ments can  be  made  more  conveniently.  A  device  which  has  sometimes 
been  employed  to  secure  a  running  load  on  the  engine  with  the  car  stand- 
ing consists  of  a  rude  form  of  Prony  brake.  A  board,  five  or  six  feet  in 
length  and  somewhat  wider  than  the  flywheel  face,  is  either  suspended 
from  the  side  frame  of  the  car  or  fulcrumed  upon  a  block  on  the  floor. 
The  short  end  of  the  lever  thus  provided  bears  against  the  flywheel  from 
the  under  side  and  weights  up  to  ten  or  fifteen  pounds  placed  on  the  other 
end  provide  all  the  load  necessary. 

With  this  apparatus  the  carburetter  may  be  adjusted  to  the  varied  road 
conditions  of  power  demands  while  the  car  is  standing. 

Changes  in  carburetter  adjustments  should  not  be  made  hurriedly  as  the 
first  impression  of  the  nature  of  a  trouble  may  prove,  on  further  investi- 
gation to  be  wrong.  When  a  fairly  good  mixture  has  been  obtained,  it 


CARBURETTERS   AND    CARBURETTING. 


243 


is  advisable  to  operate  the  car  awhile  without  further  adjustments,  not- 
ing its  behavior  and  carefully  analyzing  the  carburetter  action  under  all 
road  conditions. 

Hand  Control. — All  attempts  at  automatic  regulation  to  secure 
the  ideally  correct  mixture  of  gasoline  and  air  for  every  variation 
in  engine  speed  have  not  been  successful. 


Fio.  174.— The  Brock  Carburetter  Primary  air  enters  through  a  ring  opening  A  and 
flowing  downward,  as  indicated  by  the  arrows  meets  the  gasoline  which  enters 
through  the  slit  opening  H  in  the  walls  of  the  mixing  chamber,  the  outlet  to 
engine  being  at  K.  The  gasoline  opening  H  may  be  adjusted  by  screwing  up  or 
down  the  top  piece  C  or  cover  of  the  float  chamber.  The  float  G  maintains  a  level 
in  the  float  chamber  I),  approximately  T's  inch  above  the  gasoline  opening  H  and  in 
adjusting  this  opening,  screw  C  down  until  it  seats  firmly  at  H  then  unscrew 
about  one-eighth  turn.  At  B  is  the  secondary  air  inlet,  controlled  by  the  auxiliary 
valve  E  having  an  adjusting  screw  F.  The  float  point  has  spring  adjustment  as 
shown. 


Whatever  may  be  the  claims  of  carburetter  makers,  they  would  be  the 
first  to  admit  that,  excellent  though  the  results  may  be  in  the  hands  of 
the  average  user,  these  results  at  best  are  but  a  compromise.  Many  of  the 
best  known  European  cars  have  built  up  reputations  by  being  driven  in  and 
winning  races  on  the  road,  by  drivers  recruited  from  the  ranks  of  those 
who  first  obtained  publicity  by  track  and  road  racing  on  motor  bicycles 
having  carburetters  with  hand  control.  There  is  no  sound  reason  why  a 


244 


SELF-PROPELLED    VEHICLES. 


driver,  in  addition  to  the  throttle,  should  not  have  two  other  levers  within 
reach  to  alter  the  quantity  of  air  passing  by  the  nozzle  and  the  quantity  of 
gasoline  sprayed  into  the  mixing  chamber.  Once  the  correct  gasoline  sup 
ply  for  the  jet  is  settled  at  the  factory,  it  would  not  require  to  be  varied 
much;  therefore  an  attachment  on  the  dashboard  providing  exceedingly 
minute  gradations  would  suffice.  Hand  control  of  the  gasoline  can  ba 
used  to  advantage  in  ascending  steep  hills  when  the  engine  load  limit  is 
nearly  reached,  necessitating  wide  open  throttle  and  retarded  spark.  The 
automatic  auxiliary  air  supply  ought,  under  these  circumstances,  to 


FIG.  175.— The  Stromberg  Carburetter.  The  principal  features  of  this  carburetter 
are:  a  glass  float  chamber,  concentric  float,  veuturi  shaped  mixing  chamber, 
adjustable  primary  air  inlet,  and  a  two  spring  adjustment  for  the  auxiliary  valve. 
Jn  operation  the  gasoline  supply  is  controlled  by  the  float  F,  through  levers  J  and 
J'— the  latter  pivoted  at  P,  and  connected  to  needle  valve  N.  The  float  point  is 
.  adjustable  by  the  spring  I  and  nut  N  A.  secured  in  position  by  the  plunger  L  P. 
Primary  air  enters  at  A,  and  is  regulated  by  the  adjustable  cup  B,  secured  by  the 
plunger  B'.  The  drip  cock  C,  drains  the  float  chamber.  Tiie  mixture  from  the 
venturi  tube  V,  receives  supplementary  air  through  the  auxiliary  valve  M,  thence 
it  passes  to  engine  through  throttle  X.  The  auxiliary  valve  is  controlled  by  two 
springs  S  and  S\  the  lower  one  acts  on  moderate  speeds  and  the  upper  one  on 
high  speeds.  The  springs  have  adjusting  nuta  and  self  locking  devices  Z 
and  Z'. 


promptly  close,  but  the  tremendous  suction  exerted  by  a  four  or  six  cylin- 
der engine  on  full  throttle  does  keep  the  air  valve  open  much  wider  than 


CARBURETTERS  AND    CARBURETTING.  245 

is  essential.  The  engine  a.sks  for  the  richest  possible  mixture,  and  this 
ought  to  be  supplied,  because  the  certain  overheating  that  will  ensue  is  only 
temporary,  and  may  be  nullified  either  by  stopping  the  engine  when  the 
hill  is  surmounted  or  by  replenishing  the  circulating  water. 

The  abolition  of  hand  control  for  the  auxiliary  air  supply  is  only  for 
simplicity,  for,  with  or  without  a  variable  jet,  hand  control  offers  a  com- 
mand of  engine  flexibility  little  short  of  wonderful.  It  is  interesting  to 
watch  the  spindle  of  an  automatic  air  valve  when  the  throttle  is  opened 
and  closed,  the  car,  of  course,  being  at  a  standstill.  The  valve  will,  in 
nearly  every  case,  be  found  to  gradually  open  as  the  engine  speed  in- 
creases in  response  to  the  throttle,  reaching  its  full  opening  at  about  three- 
quarters  speed.  At  highest  speeds  the  engine  requires  considerably  more 
air  than  is  needed  at  the  lower  speeds  and  this  is  not  obtained  with  auto- 
matic control. 

A  simple  device  for  air  hand  control  may  be  applied  to  any  car  with 
little  trouble.  Cut  an  opening  at  any  suitable  place  in  the  pipe  between  the 
carburetter  and  engine  and  cover  it  with  a  sliding  collar,  valve,  flap,  or 
any  other  device  that  can  be  easily  opened  or  closed  by  a  lever  on  the  steer- 
ing column,  the  essential  feature  being  that  it  must  be  fairly  well  airtight 
in  the  closed  position. 

With  a  little  experience  on  the  road,  the  driver  will  soon  discover  the 
point  of  engine  speed  determined  by  the  throttle  lever  at  which  he  can 
commence  to  open  the  extra  air  supply.  If  he  has  never  before  driven  a 
car  so  fitted  it  will  be  a  revelation  to  him,  for  this  extra  air  port  can  be 
opened  wider  and  wider  to  an  astonishing  extent  before  the  engine  will 
misfire  to  indicate  that  the  mixture  is  too  weak. 

This  extra  air  port  besides  serving  as  a  power  increaser,  can  be  made 
to  act  as  a  scavenger  and  cylinder  cooling  agent.  When  descending  a  long 
hill,  by  switching  off  the  spark,  entirely  closing  the  throttle  and  opening 
the  extra  air  port  to  its  full  extent  (the  top  speed  gear  and  clutch  are  of 
course  kept  in  engagement  so  that  the  car  is  driving  the  engine),  cold  air 
is  drawn  into  the  engine  on  each  suction  stroke,  clearing  out  every  particle 
of  hot  gases  and  helping  materially  not  only  to  cool  the  engine  and  spark 
plugs  but  also  to  keep  the  points  of  the  latter  much  cleaner  and  freer  from 
carbonized  oil  than  would  otherwise  be  the  case. 

Carburetter  Troubles. — Preliminary  to  hunting  for  carburet- 
ter troubles,  see  that  there  is  some  gasoline  in  the  tank  and  that 
the  valve  on  the  pipe  leading  from  same  is  open.  The  carburet- 


246 


SELF-PROPELLED    VEHICLES. 


ter  is  too  often  blamed  for  faulty  engine  performance,  which 
should  be  attributed  to  defects  in  the  ignition  system.  Such  symp- 
toms as  fouled  plugs,  black  smoke  in  the  exhaust,  etc.,  point  at 
once  to  the  carburetter,  but  in  cases  where  such  obvious  signs  are 
wanting,  thoroughly  inspect  the  ignition  system  first. 

Gasoline  Leaks. — Tanks  are  liable  to  become  leaky  through 
the  opening  of  the  seams  by  jarring  or  vibration.  Galvanized 
iron  tanks,  such  as  are  furnished  on  some  machines,  should  be  dis- 
carded when  a  leak  results  from  rust,  as  it  is  practically  of  no  use 


FIG.  176.— A  Vaporizer  or  Generator  Valve.  This  differs  from  a  carburetter  In  the 
absence  of  a  float  chamber  and  consists  of  a  mixing  chamber  containing  a  check 
valve  and  having,  1,  an  air  inlet;  2,  a  gasoline  inlet;  and  3,  an  exit  to  engine.  Its 
operation  is  as  follows:  On  the  suction  stroke,  the  partial  vacuum  produced  in 
the  mixing  chamber  A  permits  the  atmospheric  pressure  to  act  upon  the  valve  F 
opening  same  against  the  tension  of  spring  G,  which  is  held  in  position  by 
the  washer  I  and  cotter  H.  At  this  period,  the  gasoline  port  in  the  valve  seat  is 
uncovered  and  a  small  amount  of  gasoline  is  sprayed  into  the  incoming  volume  of 
air  and  passing  into  the  mixing  chamber  where  the  mixing  is  further  assisted,  in 
some  designs  by  baffle  walls.  At  the  end  of  the  suction  stroke  the  pressure  in  the 
mixing  chamber  becomes  equalized  with  the  atmosphere  and  the  spring  causes 
the  valve  F  to  seat,  thereby  retaining  the  mixture  and  shutting  off  any  further 
injection  of  gasoline  or  air.  The  gasoline  supply  may  be  adjusted  by  the  needle 
valve  O  operated  by  the  thumb  wheel  P,  which  has  a  flat  spot  on  its  circumference 
on  which  the  spring  S  bears  to  retain  the  adjustment.  The  spring  can  be  turned 
to  any  position  by  loosening  the  locknut  T.  The  volume  of  mixture  to  the  engine 
is  regulated  by  a  sliding  throttle  D  operated  by  lever  M  and  locked  by  spring  N, 
which  engages  notches  in  a  graduated  dial.  The  valve  spring  G  is  held  in  position 
by  cotter  H  and  washer  I.  A  vaporizer  when  used  on  a  two  cycle  engine  requires 
no  check  valve  between  it  and  the  engine. 

to  solder  it.  A  heavy  gauge  copper  tank  should  be  substituted. 
The  supply  pipe  should  be  made  flexible  by  a  loop  to  avoid  strains 
due  to  vibration.  All  soldered  connections  should  be  inspected 
from  time  to  time. 


CARBURETTERS   AND    CARBURETTING,  247 

Leaking  Float. — Persistent  flooding  is  frequently  due  to  this 
cause.  The  presence  of  liquid  inside  a  metal  float  is  detected  by 
shaking  it,  and  the  hole  through  which  it  entered,  located  by  heat- 
ing the  float  and  passing  a  lighted  match  over  the  surface,  which 
will  ignite  the  issuing  vapor.  To  repair,  enlarge  the  hole  with 
an  awl,  drain  and  solder.  Cork  floats  sometimes  lose  their  buoy- 
ancy by  becoming  saturated  with  gasoline ;  remove  and  thoroughly 
dry  out  by  placing  the  float  in  a  warm  place,  then  apply  a  coat 
of  shellac. 

No  Flow  of  Gasoline. — Sometimes  little,  if  any,  gasoline  will 
flow  to  the  nozzle  even  when  the  carburetter  is  flooded  in  the 
usual  manner.  A  quantity  of  dirt  in  the  float  sufficient  to  stop 
the  flow  of  gasoline,  may  have  gathered  on  the  wire  gauze  in  the 


PiQ.  177.— An  Air  Inlet  Pipe.  This  consists  of  a  short  length  of  pipe  threaded  at  one 
end  and  screwed  into  the  air  inlet  of  a  vaporizer.  A  saving  in  fuel  is  secured  by 
its  nse  as  any  gasoline  or  vapor  that  may  be  blown  into  the  inlet  when  the  valve 
seats  is  retained  in  the  pipe  and  drawn  into  the  mixing  chamber  during  the  next 
suction  stroke.  Without  any  extension  of  the  inlet,  this  fuel  would  be  blown  out 
Into  the  atmosphere  and  lost 

supply  passage.  Clean  the  gauze  and  also  the  float  valve,  spray 
nozzle  and  connecting  passage.  In  removing  the  needle  valve  to 
clean  the  spray  nozzle  there  is  no  need  of  losing  the  adjustment, 
as  after  the  set  screw  which  locks  the  adjustment  is  loosened,  the 
needle  may  be  turned  down  to  a  complete  close  and  the  number  of 
turns  required  may  be  noted  from  which  the  old  setting  may  be 
again  obtained. 

Flooding. — If  not  caused  by  a  defective  float,  examine  the  float 
valve  for  imperfect  seating.  The  leak  may  usually  be  stopped  by 
grinding  the  valve  on  its  seat  with  a  little  whiting,  or  even  grind- 


248 


SELF-PROPELLED    VEHICLES. 


ing  the  seat  and  valve  together  without  any  abrasive,  holding  the 
needle  and  seat  in  their  true  relative  positions  and  giving  them 
a  motion  of  rotation  with  moderate  pressure.  Carburetters  hav- 
ing offset  float  chambers  may  flood  when  the  car  is  not  level,  as 
for  instance,  when  standing  on  a  grade. 


FIG.  178.— The  Gillett-Lehman  Economizer.    This  device,  which  may  be  applied  to 
any  float  feed  carburetter,  automatically  governs  the  air  pressure  in  the  float 


chamber.    The  main  body  A  turned  out  of  brass,  has  a  central  bore;  the  upper 
'  conical  in  shape,  the  lower  half  A"  cylindrical.    It  is  tapped  at  opposite 


half  A' 


sides  for  pipe  connections  C  and  D,  one  connecting  with  the  carburetter  mixing 
chamber  U'  the  other  with  outlet  D'  to  engine.  The  lower  end  of  A  is  connected 
by  the  nipple  E  to  top  of  the  float  chamber  which  must  be  air  tight.  At  A'  is 
fitted  a  tapered  brass  plug  M  with  a  small  vertical  hole  M'  through  it  and  a 
transverse  hole  F  through  its  top.  The  lower  end  of  this  plug  being  cut  at  an  angle, 
permits  by  turning,  adjustment  to  the  openings  C  and  D;  the  plug  being  locked 
in  position  by  cap  J.  A  screw  G  provided  with  a  lock  nut  H  makes  the  opening  F 
adjustable,  and  is  protected  by  covering^  K.  The  device  operates  as  follows: 
Being  connected  to  the  mixing  chamber,  in  which  the  vacuum  is  created  by  the 
engine,  the  atmospheric  pressure  existing  in  the  float  chamber  of  the  carburetter 
is  converted  into  a  partial  vacuum— slightly  less  than  the  vacuum  existing  in  the 
suction  tube ;  this  vacuum  increasing  or  decreasing  in  the  float  chamber  in  propor- 
tion to  the  increase  or  decrease  in  the  suction  tube,  governs  the  quantity  of  gaso 
line  issuing  at  the  spray  jet. 


CARBURETTERS   AND    CARBURETTING.  249 

Flooding  may  be  caused  by  dirt  under  the  float  valve ;  this  may 
often  be  removed  by  depressing  the  float,  thus  opening  the  float 
valve  and  flushing.  If  a  carburetter  be  not  well  stayed,  vibration 
may  keep  the  float  valve  off  its  seat,  and  continuous  flooding  re- 
sult therefrom. 

Impure  Gasoline. — Many  carburetter  troubles  would  be 
avoided  if  more  care  were  taken  to  free  gasoline  of  all  dirt  be- 
fore its  entrance  into  the  tank.  When  filling  the  tank  use  a 
strainer  funnel.  A  piece  of  chamois  skin  makes  an  excellent  fil- 
ter ;  if  a  wire  gauze  be  used  it  should  have  a  very  fine  mesh.  In 
the  absence  of  a  strainer  funnel,  use  three  or  four  layers  of  fine 
linen  fitted  inside  an  ordinary  funnel.  Never  use  the  same  funnel 
for  both  gasoline  and  water. 

Stale  Gasoline. — When  a  car  is  not  used  for  some  time  the 
gasoline  in  the  float  chamber  loses  its  strength.  If  the  engine 
should  not  start  close  the  tank  valve  and  drain  the  carburetter  by 
opening  the  pet  cock  which  is  usually  provided  in  the  bottom  of 
the  chamber  for  this  purpose.  When  empty,  close  pet  cock  and 
open  the  tank  valve,  not  forgetting  to  give  the  float  chamber  time 
to  fill  before  trying  to  start  the  engine. 

Low  Grade  Gasoline. — This  sometimes  causes  the  engine  to 
misfire  and  not  develop  its  full  power.  Inferior  fuel  is  generally 
indicated  by  a  smoky  exhaust  and  a  disagreeable  odor.  Gasoline 
suitable  for  automobile  use  should  test  76  degrees.  In 
the  absence  of  a  testing  outfit  pour  a  little  of  the  liquid  on  the 
hand.  When  it  evaporates  rapidly  and  leaves  the  hand  dry  and 
clean  it  is  acceptable,  but  if  it  evaporate  slowly  and  leaves  a 
greasy  deposit,  it  should  be  rejected.  This  furnishes  a  fairly 
reliable  indication. 

Water  in  Gasoline. — This  is  generally  indicated  when  the  en- 
gine runs  irregularly  and  finally  stops.  Place  a  small  quantity  of 
the  gasoline  on  a  clean  knife  blade  or  other  smooth  metallic  sur- 
face. The  gasoline  will  evaporate,  and  if  water  be  present  it  will 


250  SELF-PROPELLED    VEHICLES. 

collect  in  small  globules  unless  the  water  has  been  purposely 
chemically  combined  with  the  gasoline.  Gasoline  and  water 
chemically  combined  will  burn  slowly  with  a  yellowish  flame. 

Freezing  of  Carburetter. — When  water  enters  the  float  cham- 
ber it  settles  to  the  bottom  and  in  cold  weather  prevents  the  action 
of  the  float  by  freezing.  It  is  also  liable  to  enter  the  spray  nozzle 
and  stop  it  up  when  it  congeals,  as  it  may  readily  do  under  some 
conditions.  When  heavy  demands  are  made  on  a  carburetter  it 
becomes  very  cold,  as  the  heat  called  for  to  effect  evaporation  is 
more  than  that  available  from  the  entering  air.  Under  extreme 
conditions  moisture  is  deposited  in  the  form  of  frost,  indicating 
a  temperature  in  the  carburetter  too  low  for  good  working. 
These  conditions  are  avoided  by  jacketing  or  heating  the  air  sup- 
ply. 

Cold  Weather. — In  extremely  cold  weather  it  may  be  necessary 
to  warm  the  carburetter  and  admission  pipe  by  pouring  boiling 
water  over  them.  Saturate  a  piece  of  waste  with  some  fresh  gaso* 
line  and  insert  it  in  the  air  inlet  of  the  carburetter. 

Cranking. — So  far  as  carburetter  action  is  concerned,  a  few 
quick  turns  of  the  crank  will  be  more  likely  to  start  the  engine 
than  ten  minutes  of  slow  grinding. 

Misfiring. — Sometimes  caused  by  either  too  weak  or  too  rich  a 
mixture.  Misfiring  allows  the  unburnt  charge  to  accumulate  in 
the  exhaust  pipe  and  muffler;  it  is  sometimes  ignited  by  a  later 
charge  and  causes  a  loud  report  like  a  gun.  Misfiring  on  slow 
speed  may  be  caused  by  too  weak  a  mixture  due  to  having  the 
float  set  too  low,  or  by  leaks  on  the  pipe  and  connections  between 
the  throttle  and  engine. 

After  Firing. — This  is  usually  caused  by  the  delayed  ignition 
or  combustion  of  the  previous  charge,  sometimes  due  to  a  mix- 
ture that  is  too  rich  or  too  weak  and  hence  burns  slowly,  continu- 
ing its  combustion  after  passing  into  the  exhaust, 


CARBURETTERS   AND    CARBURHTTING. 


Weak  Explosions. — Regular  but  weak  explosions  may  be  due 
to  either  too  rich  or  too  poor  a  mixture,  or  to  the  loss  of  compres- 
sion. A  hiss  inside  the  cylinder  indicates  a  leaky  piston  ring  or 
that  the  openings  of  the  piston  rings  are  in  line.  A  little  soapy 
water  around  the  relief  cock,  spark  plug  or  other  opening  into 
the  combustion  space  will  indicate  a  loss  of  compression  by  the 
formation  of  bubbles. 


FIG.  179.— The  Marvel  Carburetter.  The  particular  feature  of  this  carburetter  Is 
the  damper  H,  for  regulating  the  fuel  flow  out  of  the  nozzle  A  independent  of 
the  needle  valve  adjustment  B.  The  operation  is  as  follows:  With  damper 
ck>sed  (position  H)  a  strong  suction,  is  produced,  increasing  the  strength  of  the 
mixture.  When  the  damper  is  opened  as  in  position  H';  the  suction  is  reduced 
and  hence  the  strength  of  the  mixture  likewise.  The  damper  may  be  swung  to 
and  fro  through  the  handle  K  which  also  has  connection  with  the  throttle  valve 
D.  The  connection  P,  to  gasoline  tank  may  be  swung  into  any  direction  by 
loosening  locknut  N.  By  releasing  screw  B,  the  hot  air  connection  F  may  be 
turned  to  any  convenient  angle.  Again,  by  releasing  the  two  nuts  S,  the  engine 
connection  E  may  be  turned  to  any  other  position  as  E'  convenient  for  piping. 
The  float  chamber  M  is  removable  by  unscrewing  nut,  N.  The  float  point  has 
spring  adjustment,  accessible  by  removing  cap  Z. 


252 


SELF-PROPELLED  VEHICLES. 


Denatured  Alcohol. — This  consists  of  ethyl  spirit,  or  the 
common  spirit  cf  wine,  mixed  with  methyl  alcohol,  or  wood  spirit 
and  some  other  hydrocarbon.  The  object  of  mingling  the  spirit 
with  the  other  ingredients  is  to  prevent  its  being  drunk. 

In  using  alcohol,  heat  must  be  supplied  to  the  carburetter  for 
complete  vaporization.  One  type  of  alcohol  carburetter,  shown 
in  Fig.  180,  is  double,  the  engine  being  started  with  gasoline, 
and  run  with  alcohol  as  soon  as  the  speed  is  sufficient  to  generate 
a  high  temperature.  The  alcohol  is  then  turned  on  by  the  rotary 
cock  valve,  B. 


A/coM 


Gaso/ene 


FIG.  180. — A  double  float-feed  carburetter  for  alcohol  and  gasoline.  A, 
float  in  gasoline  chamber;  B,  rotary  valve  controlling  outlet  of 
alcohol  or  gasoline  to  engine  space,  through  nozzles,  C  or  E;  D,  float 
in  alcohol  chamber;  F,  butterfly  valve  for  controlling  volume  of 
fuel  charge. 

Conditions  of  Using  Alcohol  Fuel. — The  successful  use  of 
alcohol  as  a  fuel  for  a  gas  engine  involves  the  following  con- 
ditions: 

i.  For  complete  vaporization  of  the  alcohol  heat  is  necessary. 
For  this  reason  the  carburetter  is  frequently  heated  by  the  exhaust 
pr  by  water  jacketing-. 


CARBURETTERS  AND    CARBURET  TING.  253 

2.  A  higher  compression  than  is  commonly  used  with  gasoline 
is  necessary,  in  order  to  obtain  as  high  a  power  efficiency  a.s 

possible. 

3.  Reliable  sparking  devices  are  essential,  in  order  to  produo- 
complete  combustion,  preventing  injurious  acid  products  liable  to 
result  from  water  vapors  and  incomplete  combustion. 

Useful  Alcohol  Data. — The  following  conclusions  regarding 
the  use  of  alcohol  as  fuel  for  engines  as  compared  with  gasoline 
are  based  on  the  results  of  recent  experiments : 

1.  Any   engine  operating  with  gasoline   or  kerosene    can  operate    with 
alcohol  fuel  without  any  structural  change  whatever,  with  proper  manipu- 
lation. 

2.  It  requires  no  more  skill  to  operate  an  alcohol  engine  than  one  in- 
tended for  gasoline  or  kerosene. 

3.  There  seems  to  be  no  tendency  for  the  interior  of  an  alcohol  engine 
to  become  sooty,  as  is  the  case  with  gasoline  and  kerosene. 

4.  Alcohol  contains  approximately  0.6  of  the  heating  value  of  gasoline, 
by  weight;  a  small  engine  requires  1.8  times  as  much  alcohol  as  gasoline 
per   horse   power  hour.     This  corresponds   very  closely  with   the  relative 
heating  value  of  the  fuels,  indicating  practically  the  same  thermal  efficiency 
of  the  two  when  vaporization  is  complete. 

5.  In  some  cases  carburetters  designed  for  gasoline  do  not  vaporize  all 
the  alcohol  supplied,  and  in  such  cases  the  excess  of  alcohol  consumed  is 
greater  than  indicated  above. 

6.  The  absolute  excess  of  alcohol  consumed  over  gasoline  or  kerosene 
will  be  reduced  by  such  changes  as  will  increase  the  thermal  efficiency  of 
the  engine. 

7.  The  thermal  efficiency  of  these  engines  can  be  improved  when  they 
are  to  be  operated  by  alcohol,   first  by  altering  the  construction  of  the 
carburetter  to  accomplish  complete  vaporization,  and  second,  by  increasing 
the  compression  very  materially. 

8.  An  engine  designed  for  gasoline  or  kerosene  can,  without  any  ma- 
terial alterations  to  adapt  it  to  alcohol,  give  slightly  more  power  (about 
10  per  cent.)  than  when  operated  with  gasoline  or  kerosene,  but  this  in- 
crease is  at  the  expense  of  greater  consumption  of  fuel.     By  alterations 
designed  to  adapt  the  engine  to  new  fuel  this  excess  of  power  may  be  in- 
creased to  about  20  per  cent. 

9.  The  different  designs  of  gasoline  or  kerosene  engines  are  not  equally 
well  adapted  to  the  burning  of  alcohol,  though  all  may  burn  it  with  a  fair 
degree  of  success. 


g-i-l  SELF-PROPELLED  VEHICLES. 

TO.  Storage  of  alcohol  and  its  use  in  engines  is  much  less  dangerous 
than  that  of  gasoline,  as  well  as  being  decidedly  more  pleasant. 

11.  The  exhaust   from  an  alcohol  engine  is  less  likely  to  be  offensive 
than  the  exhaust  from  a  gasoline  or  kerosene  engine,  although  there  will 
be  some  odor,  due  to  lubricating  oil  and  imperfect  combustion,  if  the  en- 
gine be  not  skillfully  operated. 

12.  With  proper  manipulation,  there  seems  to  be  no  undue  corrosion  of 
the  interior  due  to  the  use  of  alcohol. 

13.  The  fact  that  the  exhaust  from  the  alcohol  engine  is  not  as  hot  as 
that  from  gasoline  and  kerosene  seems  to  indicate  less  possibility  of  burn- 
ing the  lubricating1  oil.     This  is  borne  out  by  the  fact  that  the  exhaust 
shows  less  smoke. 

14.  In  localities  where  there  is  a  supply  of  cheap  raw  material  for  the 
manufacture  of  denatured  alcohol,  and  which  are  at  the  same  time  remote 
from  the  source  of  supply  of  gasoline,  alcohol  may  immediately  compete 
with  gasoline  as  a  fuel  for  engines. 

15.  There  is  no  reason  to  suppose  that  the  cost  of  repairs  and  lubrication 
will  be  any  greater  for  an  alcohol  engine  than  for  one  built  for  gasoline 
or  kerosene. 

A  carburetter  designed  for  alcohol  may  be  used  with  gasoline, 
but  the  reverse  conditions  are  not  true.  The  time  required  for  the 
evaporation  and  combustion  of  alcohol  is  greater  than  that  re- 
quired for  gasoline,  but  a  higher  mean  effective  pressure  is  realized 
with  alcohol  than  with  gasoline.  Moreover  when  alcohol  is  used 
as  a  fuel  the  noise  of  operation  is  reduced. 

The  power  efficiency  of  alcohol  has  been  given  as  slightly  over 
I  pint  per  horse  power,  according  to  purity.  The  figure  for  gaso- 
line is  generally  given  as  about  .86  pint  per  horse  power.  An 
interesting  test  of  power  efficiency  has  been  made  with  a  motor 
vehicle  used  for  dragging  a  plow.  With  2  gallons  of  gasoline  3 
roods  were  plowed ;  with  2  gallons  of  kerosene,  3  roods,  35  poles ; 
with  two  gallons  of  alcohol,  2  roods,  25  poles. 


CHAPTER    TWENTY-FIVE. 

IGNITION. 

Introductory. — Ignition  is  a  subject  of  much  importance  in 
automobiling  and  one  that  is  perplexing  to  the  novice.  The  en- 
gine may  operate  with  an  imperfect  fuel  mixture,  if  the  ignition 
system  be  in  working  order,  but  any  defect  in  the  latter  will  in 
nearly  every  case  cause  the  engine  to  misfire  or  stop. 

Numerous  devices  have  been  tried  to  fire  the  charge  in  gas  engines.  In 
the  early  days,  a  flame  behind  a  shutter  was  used,  the  latter  being  opened 
at  the  proper  moment.  Sometimes  the  flame  was  blown  out  by  a  too  vio- 
lent explosion,  so  this  method  gave  way  to  a  porcelain  tube  that  was  kept  at 
white  heat  by  an  interior  flame.  The  tube  being  subject  to  breakage, 
spongy  platinum,  heated  by  compression,  was  next  tried  and  found  to 
work,  if  not  too  moist  from  watery  vapor  in  the  gas  mixture,  or  if  the 
engine  speed  were  not  too  high.  The  heat  of  high  compression  was  also 
tried  and  is  in  successful  use  to-day  for  stationary  engines,  but  seems  as 
yet  not  to  meet  automobile  requirements. 

Electricity  is  now  universally  used.  Hence,  in  order  to  gain  a  clear 
understanding  of  ignition  principles  it  is  necessary  to  have  at  least  an 
elementary  knowledge  of  electricity  of  which  a  short  introduction  is  here 
given.  This  should  be  supplemented  by  reading  the  other  electrical  por- 
tions of  the  book. 

Electricity. — The  name  electricity  is  applied  to  an  invisible 
agent  known  only  by  the  effects  which  it  produces,  and  the  vari- 
ous ways  in  which  it  manifests  itself. 

Electrical  currents  are  said  to  flow  through  conductors.  These  offer 
more  or  less  resistance  to  the  flow,  depending  on  the  material.  Copper 
wire  is  generally  used  as  it  offers  little  resistance  to  the  flow  of  the 
current.  It  is  now  thought  that  the  flow  takes  place  along  the  surface 
and  not  through  the  metal.  The  current  must  have  pressure  to  over- 
come the  resistance  of  the  conductor  and  flow  along  its  surface.  This 
pressure  is  called  voltage  caused  by  what  is  known  as  difference  of 
potential  between  the  source  and  terminal. 

An  electric  current  has  often  been  compared  to  water  flowing  through 
a  pipe.  The  pressure  under  which  the  current  flows  is  measured  in  volts 
and  the  quantity  that  passes  in  amperes.  The  resistance  with  which  the 
current  meets  in  flowing  along  the  conductor  is  measured  in  ohms.  The 
flow  of  the  current  is  proportional  to  the  voltage  and  inversely  propor- 
tional to  the  resistance.  The  latter  depends  upon  the  material,  length 
and  diameter  of  the  conductor. 

855 


256  SELF-PROPELLED     VEHICLES. 

Since  the  current  will  always  flow  along  the  path  of  least  resistance  it 
must  be  so  guarded  that  there  will  be  no  leakage.  Hence  to  prevent  leak- 
age, wires  are  insulated,  that  is,  covered  by  wrapping  them  with  cotton 
or  silk  thread  or  other  non-conducting  materials.  If  the  insulation  be  not 
effective,  the  current  may  leak,  and  so  return  to  the  source  without  doing 
its  work.  This  is  known  as  a  short  circuit. 

The  conductor  which  receives  the  current  from  the  source  is  called 
the  lead  and  the  one  by  which  it  flows  back,  the  return.  When  wires 
are  used  for  both  lead  and  return,  it  is  called  a  metallic  circuit;  when 
the  metal  of  the  engine  is  used  for  the  return,  it  is  called  a  grounded 
circuit,  the  term  originating  in  telegraphy,  where  the  earth  is  used  for 
the  return.  In  ignition  diagrams  then  the  expression  "to  ground"  means 
to  the  metal  of  the  engine. 

An  electric  current  may  do  work  of  various  kinds,  but  the  one  prop- 
erty which  makes  it  available  for  ignition  is  the  fact  that  whenever  its 
motion  is  stopped  by  interposing  a  resistance,  the  energy  of  its  flow  is 
converted  into  heat.  In  practice  this  is  accomplished  in  two  ways :  I,  by 
suddenly  breaking  a  circuit,  2,  by  placing  in  the  circuit  a  permanent  air 
gap  which  the  current  must  jump.  In  either  case,  the  intense  heat  caused 
by  the  enormous  resistance  interposed,  produces  a  spark  which  is  utilized 
to  ignite  the  charge.  The  first  method  is  known  as  the  make  and  break 
or  low  tension  and  the  second,  the  jump  spark  or  high  tension. 

An  electric  current  is  said  to  be:  I,  direct,  when  it  is  of  unvarying 
direction ;  2,  alternating,  when  it  flows  rapidly  to  and  fro  in  opposite 
directions;  3,  primary,  when  it  comes  directly  from  the  source;  4,  second- 
ary, when  the  voltage  and  amperage  of  a  primary  current  have  been 
changed  by  an  induction  coil.  A  current  is  spoken  of  as  loia  tension,  or 
high  tension,  according  as  the  voltage  is  low  or  high.  A  high  tension 
current  is  capable  of  forcing  its  way  against  considerable  resistance, 
whereas,  a  low  tension  current  must  have  its  path  made  easy.  A  con- 
tinuous metal  path  is  an  easy  one,  but  an  interruption  in  the  metal,  as, 
the  permanent  air  gap  of  a  spark  plug,  is  difficult  to  bridge,  because  air 
is  a  very  poor  conductor.  Air  is  such  a  poor  conductor  that  it  is  usually 
spoken  of  as  a  non-conductor.  The  low  tension  current  is  only  able  to 
produce  a  spark  when  parts  are  provided  in  the  path,  so  arranged  that 
they  may  be  in  contact  and  then  suddenly  separated.  The  low  tension 
current  will,  as  the  separation  occurs,  tear  off  very  small  metallic  par- 
ticles and  use  these  "as  a  bridge  to  keep  the  path  complete.  Such  a  bridge 
is  called  an  arc,  the  heat  of  which  is  used  for  ignition. 

Magnetism. — The  ancients  applied  the  word  "magnet," 
magnes  lapcs,  to  certain  hard  black  stones  which  possess  the 
property  of  attracting  small  pieces  of  iron,  and  as  discovered 
later,  to  have  the  still  more  remarkable  property  of  pointing 
north  and  south  when  hung  up  by  a  string ;  at  this  time  the  mag- 
net received  the  name  lodestone.  The  automobile  word  mag- 
neto is  derived,  as  may  easily  be  understood,  from  the  word 
magnet. 

Magnets  have  two  opposite  kinds  of  magnetism  or  magnetic  poles, 
which  attract  or  repel  each  other  in  much  the  same  way  as  would  two 


IGNITION.  257 

opposite  kinds  of  electrification.  One  of  these  kinds  of  magnetism  has  a 
tendency  to  move  toward  the  north  and  the  other,  toward  the  south. 
The  two  regions,  in  which  the  magnetic  property  is  strongest,  are 
called  the  poles.  In  a  long  shaped  magnet  it  resides  in  the  ends,  while  all 
around  the  magnet  half  way  between  the  poles  there  is  no  attraction  at  all. 
The  poles  of  a  magnet  are  usually  spoken  of  as  north  pole  and  south 
pole. 

When  a  current  of  electricity  passes  through  a  wire,  a  certain  change  is 
produced  in  the  surrounding  space  producing  what  is  known  as  a 
magnetic  field.  If  the  wire  be  insulated  with  a  covering  and  coiled 
around  a  soft  iron  rod,  it  becomes  an  electro-magnet  having  a  north  and 
south  pole,  so  long  as  the  current  continues  to  How.  The  magnetic 
strength  increases  with  the  number  of  turns  of  the  coil,  for  each  turn 
adds  its  magnetic  field  to  that  of  the  other  turns. 

Induction. — If  a  second  coil  of  wire  be  wound  around  the 
coil  of  an  electro-magnet,  but  not  touching  it,  an  induced  current 
is  produced  in  this  second  coil  by  what  is  known  as  induction, 
each  time  the  current  in  the  inside  coil  begins  or  ceases  flowing. 
The  inside  coil  is  called  the  primary  -winding  and  the  outside 
coil  the  secondary  minding.  Similarly,  the  current  passing 
through  the  inside  coil  is  called  the  primary  current  and  that  in 
the  outside  coil  the  secondary  or  induced  current. 

It  has  been  found  that  by  varying  the  ratio  of  the  number  of  turns  in 
the  two  coils  the  tension  or  voltage  of  the  two  currents  is  changed  pro- 
portionately. That  is,  if  the  primary  winding  be  composed  of  ten  turns 
and  the  secondary  of  one  hundred,  the  voltage  of  the  secondary  current 
is  increased  ten  times  that  of  the  primary.  This  principle  is  employed 
to  produce  the  extremely  high  tension  current  necessary  with  the  jump 
spark  method  of  ignition. 

Methods  of  Producing  Electricity. — Currents  are  produced 
by,  i,  chemical  and,  2,  mechanical  means.  In  the  first  method,  two 
dissimilar  metals  such  as  copper  and  zinc  called  electrodes  are 
immersed  in  an  exciting  fluid  or  dielectric.  When  the  electrodes 
are  connected  at  their  terminals  by  a  wire  or  conductor,  a  chemi- 
cal action  takes  place,  producing  a  current  which  flows  from 
the  copper  to  the  zinc.  This  device  is  called  a  cell,  and  the  com- 
bination of  two  or  more  of  them  connected  so  as  to  form  a  unit, 
is  known  as  a  battery.  The  word  battery  is  frequently  used  in- 
correctly for  a  single  cell.  That  terminal  of  the  electrode  from 
which  the  current  flows  is  called  a  plus  or  positive  pole  and  the 
other  electrode  terminal  a  negative  pole. 


£58  SELF-PROPELLED    VEHICLES. 

Cells  are  said  to  be  primary  or  secondary  according  as  they  generate 
a  current  of  themselves  or  first  require  to  be  charged  from  an  external 
source,  storing  up  a  current  supply  which  is  afterwards  yielded  in  the 
reverse  direction  to  that  of  the  charging  current. 

There  are  two  methods  of  producing  an  electric  current  by  mechanical 
means,  i,  by  a  dynamo  and  2,  by  a  magneto. 

A  dynamo  has  an  electro-magnet  which  is  known  as  a  field  magnet  to 
produce  a  magnetic  field  and  an  armature  which  when  revolved  in  the 
magnetic  field  develops  electric  current. 

A  magneto  has  a  permanent  magnet  to  produce  the  magnetic  field  and 
an  armature  which  is  usually  arranged  to  revolve  between  the  poles  of 
the  magnet.  The  basic  principles  upon  which  dynamos  and  magnetos 
operate  are  the  same.  Magnetos  are  divided  into  two  classes,  i,  low  ten- 
sion and  2,  high  tension  according  as  they  generate  a  current  of  low  or 
high  voltage.  Low  tension  magnetos  are  used  for  make  and  break  igni- 
tion and  the  high  tension  type  for  the  jump  spark  system.  A  low  ten- 
sion magneto  in  combination  with  a  secondary  induction  coil  may  be 
used  to  produce  a  high  tension  spark. 

Primary  Cells. — There  are  various  types  of  primary  cells; 
those  known  as  dry  cells  are  most  frequently  used. 

A  dry  cell  is  composed  of  three  elements,  usually  zinc,  carbon 
and  a  liquid  electrolyte.  A  zinc  cup  closed  at  the  bottom  and 
open  at  the  top  forms  the  negative  electrode;  this  is  lined  with 
several  layers  of  blotting  paper  or  other  absorbing  material. 

The  positive  electrode  consists  of  a  carbon  rod  placed  in  the 
center  of  the  cup;  the  space  between  is  filled  with  carbon — 
ground  coke  and  dioxide  of  manganese  mixed  with  an  absorbent 
material.  This  filling  is  moistened  with  a  liquid,  generally  sal- 
ammoniac.  The  top  of  the  cell  is  closed  with  pitch  to  prevent 
leakage  and  evaporation.  A  binding  post  for  holding  the  wire 
connections  is  attached  to  each  electrode  and  each  cell  is  placed 
in  a  paper  box  to  protect  the  zincs  of  adjacent  cells  from  coming 
into  contact  with  each  other,  when  finally  connected  together  to 
form  a  battery. 

The  average  voltage  of  a  dry  cell  when  new  is  one  and  one-half  volts, 
while  the  amperage  ranges  from  about  twenty-five  to  fifty  amperes  accord- 
ing to  size.  Now,  since  it  requires  about  six  volts  for  the  proper  working 
of  a  coil,  one  cell  is  not  sufficient;  hence  several  must  be  used. 

There  are  three  methods  of  connecting  cells,  i,  in  series,  2,  in  parallel 
or  multiple  and  3,  in  series  multiple. 

A  series  connection  consists  in  joining  the  positive  pole  of  one  cell  to 
the  negative  pole  of  the  other  as  shown  in  fig.  181 ;  this  adds  the  voltage 
of  each  cell.  Thus,  connecting  in  series  four  cells  of  one  and  one-half 


IGNITION. 


25S 


FIG.  181. — Diagram  of  a  series  battery  connection:  four  cells  are  shown 
connected  by  this  method.  If  the  cell  voltage  be  one  and  one-half 
volts,  the  pressure  between  the  (+)  and  ( — )  terminals  of  the 
Itnitery  is  equal  to  the  product  of  the  voltage  of  a  single  cell  multi- 
plied by  the  number  of  cells.  For  four  cells  it  is  equal  to  six  volts. 

volts  each  will  give  a  total  of  six  volts.  Fig  182  illustrates  a  parallel 
or  multiple  connection ;  this  is  made  by  connecting  the  positive  terminal 
of  one  cell  with  the  positive  terminal  of  another  cell  and  the  negative 
terminal  of  the  first  cell  with  the  negative  terminal  of  the  second  cell. 
A  parallel  or  multiple  connection  adds  the  amperage  of  each  cell;  that  is, 
the  amperage  of  the  battery  will  equal  the  sum  of  the  amperage  of  each 
cell.  For  instance,  four  cells  of  twenty-five  amperes  each  would  give  a 
total  of  one  hundred  amperes  when  connected  in  parallel.  A  series  mul- 


FIG.  182. — Diagram  of  a  multiple  or  parallel  connection.  When  connected 
in  this  manner  ihe  voltage  of  the  battery  is  the  same  as  that  of  a 
single  cell,  but  the  amperage  of  the  battery  is  equal  to  the 
amperage  of  a  single  cell  multiplied  by  the  number  of  cells. 


PIG.  183. — Diagram  of  a  series  multiple  connection.  Two  sets  of  cells  are 
connected  in  series,  and  the  two  batteries  thus  formed,  connected  in 
parallel.  The  pressure  equals  the  voltage  of  one  cell,  multiplied  by 
the  number  of  cells  in  one  battery,  and  the  amperage,  that  of  one 
cell  multiplied  by  the  number  of  batteries. 


tiple  connection,  fig.  183,  consists  of  connecting  two  sets  of  cells  in  series 
and  then  connecting  the  two  sets  in  parallel.  In  series  multiple  con- 
nections the  voltage  of  each  set  of  cells  or  battery  must  be  equal,  or  the 
batteries  will  be  weakened,  hence  each  battery  of  a  series  multiple  con- 
nection should  contain  the  same  number  of  cells.  The  voltage  of  a  series 
multiple  connection  is  equal  to  the  voltage  of  one  cell  multiplied  by  the 
number  of  cells  in  one  battery  and  the  amperage  is  equal  to  the  amper- 
age of  one  cell  multiplied  by  the  number  of  batteries. 


260  SELF-PROPELLED    VEHICLES. 

Fig.  184  shows  an  incorrect  method  of  wiring  in  series  multiple 
connection.  If  the  circuit  be  open,  the  six  cells,  on  account  of 
having  more  electromotive  force  than  the  four  cells,  will  over- 
power them  and  cause  a  current  to  flow  in  the  direction  indicated 
by  the  arrows  until  the  pressure  of  the  six  cells  has  dropped  to 
that  of  the  four.  This  will  use  up  the  energy  of  the  six  cells, 
but  will  not  weaken  the  four  cell  battery.  This  action  can  be 
corrected  by  placing  a  two-way  switch  in  the  circuit  at  the  junc- 
tion of  the  two  negative  terminals  so  that  only  one  battery  can 
be  used  at  a  time. 


FIG.  184. — Diagram  to  illustrate  incorrect  wiring1.  The  current  pressure 
of  the  six  cell  battery  being  greater  than  that  of  the  smaller  unit, 
current  will  flow  from  the  former  through  the  latter  until  the 
pressure  of  the  six  cells  is  equal  to  that  of  the  four  cells. 

Two  batteries  should  be  provided  and  used  alternately  so  that  one  can 
recuperate  while  the  other  is  in  use ;  the  stronger  should  be  used  in 
starting. 

In  renewing  dry  cells  a  greater  number  should  never  be  put  in  series 
than  originally  came  with  the  machine.  With  a  good  coil,  four  to  six 
cells  in  scries  will  give  satisfactory  service  on  most  machines,  and 
if  four  cells  suffice,  then  a  greater  number  connected  in  series  will  last 
a  shorter  length  of  time.  This  is  because  the  additional  cells  increase  the 
voltage  beyond  that  required  and  likewise  cause  more  current  than  is 
necessary,  to  How  through  the  coil ;  this  increased  current  flow  of  course 
shortens  the  life  of  the  battery. 

In  connecting  dry  cells  heavy  copper  wire  should  not  be  used,  because 
vibration  may  cause  it  to  break.  The  terminals  should  be  tightly  con- 
nected and  the  spark  plugs  kept  clean.  When  washing  the  machine, 
water  should  not  come  in  contact  with  the  dry  cells,  because  the  paper 
covers  forming  the  insulation  will  become  moist  and  the  current  leak 
across  from  one  cell  to  another,  resulting  in  running  down  the  battery. 

When  a  motor  will  run  at  high  speed  without  missing  explosions,  white 
the  car  is  standing,  but  will  miss  under  road  conditions,  it  indicates  that 
the  battery  is  weak.  If  this  condition  occur,  each  cell  should  be  tested 
separately,  as  often  only  one  of  them  has  weakened,  and  it  is  only  neces- 
sary to  replace  the  weak  ones.  This  should  be  done  at  once,  as  the  weak 
cell  will  destroy  the  strength  of  the  others.  A  weak  battery  frequently 


IGNITION.  261 

causes  trouble  in  starting,  as  a  better  spark  is  then  required  than  when 
the  motor  is  warm.  Extra  milage  can  be  secured  from  two  run  down 
batteries  by  connecting  them  in  series  multiple. 

As  batteries  become  weak  a  slight  change  of  vibrator  adjustment  will 
prolong  their  life.  Care  should  be  taken  when  adjusting  coils  so  as  to 
use  as  little  current  as  possible.  The  vibrator  should  be  screwed  down 
sufficiently  to  give  just  enough  spark  to  run  the  motor;  the  closer  the 
points  are  the  more  current  will  be  used.  One-third  ampere  current  is 
the  average  amount  necessary.  A  half  turn  of  the  adjusting  screw  on  a 
coil  will  often  increase  the  current  consumed  by  the  coil  from  one-half 
up  to  one  and  one-half  amperes  or  nearly  five  times  the  actual  amount 
necessary. 

Dry  cells  will  deteriorate  when  not  in  use,  making  it  necessary  to  re- 
new them  about  every  sixty  days.  It  will  be  economy  to  do  this,  as  the 
saving  in  gasoline  will  more  than  offset  the  additional  battery  cost ;  the 
reason  dry  cells  deteriorate  is  because  the  moisture  evaporates.  Freezing, 
exposure  to  heat,  and  vibration  which  loosens  the  sealing,  causes  the 
evaporation. 

Weak  cells  can  be  strengthened  somewhat  by  removing  the  paper  jacket 
and  punching  the  metal  cups  full  of  small  holes ;  and  then  placing  in  a 
weak  solution  of  sal-ammoniac,  allowing  the  cells  to  absorb  all  they  will 
take  up.  This  is  only  to  be  recommended  in  cases  of  emergency  when 
they  are  hard  to  get.  Each  cell  when  fresh  should  show  from  20  to  25 
amperes  when  tested ;  the  date  of  manufacture  should  also  be  noted  as 
fresh  cells  are  most  efficient. 

It  is  well  not  to  put  cells  of  various  voltages  or  of  different  makes  in 
the  same  circuit,  for  the  stronger  will  discharge  into  the  weakest  until  all 
are  equal.  Dry  cells  should  be  tested  with  an  ammeter,  care  being  taken 
to  do  it  quickly  as  the  ammeter  being  of  a  very  low  resistance  short 
circuits  the  cell.  A  voltmeter  is  not  used  in  testing  because  while  the 
cells  are  not  giving  out  current,  their  voltage  remains  practically  the  same, 
and  a  cell  that  is  very  weak  will  show  nearly  full  voltage.  When  no 
ammeter  is  at  hand  the  battery  current  may  be  tested  by  disconnecting 
the  end  of  one  of  the  terminal  wires  and  snapping  it  across  the  binding 
post  of  the  other  terminal ;  the  intensity  of  the  spark  produced  will  in- 
dicate the  condition  of  the  battery. 

Secondary  Cells. — A  second  chemical  means  of  producing 
electricity  for  ignition  is  the  storage  battery  which  consists  of 
two  or  more  secondary  cells  contained  in  a  carrying  case  or  box 
usually  of  Wood  or  hard  rubber.  A  secondary  cell  is  made  up  of 
a  positive  and  a  negative  set  of  lead  plates  immersed  in  an  elec- 
trolyte of  dilute  sulphuric  acid.  The  proportion  of  acid  to  water 
is  about  one  part  acid  to  three  and  one-half  parts  of  water.  In 
preparing  the  electrolyte,  acid  should  always  be  added  to  water — 
not  water  to  acid. 

In  passing  an  electric  current  through  a  cell  the  plates  undergo 
a  chemical  change;  when  this  is  complete  the  cell  is  said  to  be 


262  SELF-PROPELLED    VEHICLES. 

charged.  A  quantity  of  electricity  has  been  stored  in  the  cell, 
hence  the  name,  storage  battery.  The  cell  after  being  charged 
will  deliver  a  current  in  a  reverse  direction  because  during  the 
discharge  a  reverse  chemical  action  takes  place  which  causes  the 
plates  to  resume  their  original  condition.  When  fully  charged 
the  positive  plates  are  coated  with  peroxide  of  lead  and  are  brown 
in  color  and  the  negative  plates  gray. 

As  the  general  theory,  construction  and  management  of  storage  bat- 
teries are  outlined  in  a  later  chapter,  it  will  be  necessary  to  say  little  here 
regarding  them. 

The  positive  and  negative  poles  of  a  secondary  cell  are  plainly  marked 
-j-  and  —  or  P  and  N.  A  cell  when  fully  charged  has  a  pressure  of  about 
two  and  one-half  volts. 

When  current  is  taken  from  a  cell  the  voltage  drops,  and  when  1.8 
volts  is  reached,  the  cell  must  be  recharged.  Unless  this  be  done  im- 
mediately the  cell  will  deteriorate.  The  secondary  cells  forming  a  stor- 
age battery  should  be  connected  in  series.  For  ignition  service  the  battery 
capacity  generally  used  is  rated  at  40  ampere  hours.  A  battery  of  this 
capacity  is  composed  of  three  cells  having  a  total  pressure  of  six  volts. 

A  storage  battery  should  be  charged  once  every  two  months  whether 
it  be  used  or  not.  In  charging,  a  direct  current  should  be  used — never 
an  alternating  one,  care  being  taken  to  connect  the  positive  wire  to  the 
positive  terminal  and  the  negative  wire  to  the  negative  terminal.  If 
connected  in  the  reverse  direction  serious  injury  to  the  battery  will  re- 
sult. The  simplest  method  of  charging  is  from  an  incandescent  light 
circuit,  using  lamps  connected  in  parallel  to  reduce  the  voltage  to  that  of 
the  battery,  the  current  being  adjusted  by  varying  the  number  of  lamps  in 
the  circuit.  The  group  of  lamps  is  connected  in  series  with  the  battery  to 
be  charged,  and  the  combination  connected  across  the  circuit  furnishing 
the  current.  If  the  charging  source  be  a  110-120  volt  circuit,  and  the  rate 
required  be  6  amperes,  twelve  16  c.  p.  or  six  32  c.  p.  lamps,  in  parallel,  and 
the  group  in  series  with  the  battery,  will  give  the  desired  charging  rate, 
unless  special  high  efficiency  lamps  be  used,  when  more  will  be  required, 
In  case  a  lower  charging  rate,  say  2  amperes,  be  used,  then  a  proportion- 
ately fewer  number  of  lamps  will  be  needed ;  but  the  length  of  time  re- 
quired to  complete  the  charge  will  be  correspondingly  increased. 

Instead  of  lamps,  a  rheostat  is  sometimes  used.  Its  resistance  should 
be  such  as  to  produce,  when  carrying  the  normal  charging  current,  a  drop 
in  volts  equal  to  the  difference  between  the  pressure  of  the  charging 
source  and  that  of  the  battery  to  be  charged;  thus,  if  a  battery  of  three 
cells  giving  6  volts,  is  to  be  charged  from  a  no-volt  circuit  at  a  6-ampere 
rate,  the  resistance  would  be,  according  to  Ohm's  law, 

no — 6  volts 

•  =  17.3  ohms. 


6  amperes 

The  carrying  capacity  of  the  rheostat  should  be  slightly  in  excess  of  the 
current   required   for  charging  the  battery,     An  ammeter  with   suitable 


IGNITION.  263 

scale  should  be  inserted  in  the  battery  circuit  to  indicate  the  quantity 
flowing.  A  battery  should  be  charged  at  the  rate  given  on  the  name  plate 
on  the  case,  until  there  is  no  further  rise  in  its  voltage  and  each  cell  has 
been  gassing  or  bubbling  freely  for  at  least  five  hours,  and  there  is  also 
no  further  rise  in  the  specific  gravity  of  the  electrolyte  over  the  same 
period.  The  voltage  at  the  end  of  the  charge  may  be  between  2.40  and 
2.70  volts  per  cell,  depending  on  the  temperature  and  age ;  the  higher 
voltages  are  obtained  on  new  batteries  with  the  temperature  low;  on  old 
batteries  at  high  temperatures  the  lower  voltages  are  obtained. 

It  therefore  must  be  understood  that,  in  determining  the  completion  of 
a  charge,  a  fixed  or  definite  voltage  is  not  to  be  considered,  but  rather 
a  maximum  voltage,  as  indicated  by  there  being  no  further  rise  in  the 
voltage  over  a  period  of  five  hours.  It  is  important  that  the  charge  be  com- 
plete. The  temperature  of  the  electrolyte  while  charging  should  not  be 
allowed  to  rise  above  100°  Fahr.  Low  temperatures  do  not  injure  a  bat- 
tery, but  have  the  effect  of  temporarily  reducing  its  discharge  capacity. 

The  specific  gravity  of  the  electrolyte  at  the  end  of  the  charge  should 
be  1.3.  The  specific  gravity  should  not  be  altered  when  the  battery  is 
fully  charged.  After  changing  the  gravity,  the  battery  should  be  charged 
for  an  hour  to  thoroughly  mix  the  liquid  just  added.  To  add  water  or 
electrolyte,  or  to  remove  surplus  electrolyte,  a  rubber  syringe  is  employed. 
A  flame  should  not  be  brought  near  the  battery  during  or  immediately  fol- 
lowing the  charge. 

One  of  the  destroying  elements  of  storage  batteries  is  sulphation  of  the 
plates.  This  sulphate  of  lead  is  deposited  on  the  plates  in  the  form  of  a 
very  hard  grayish  coating.  It  is  practically  a  non-conductor  and  in  con- 
sequence plates  so  affected  are  rendered  useless  unless  it  be  removed. 

There  are  many  causes  for  sulphation,  among  which  are,  too  strong  or 
too  hot  electrolyte,  over  discharging,  etc.  The  most  common  cause  of 
sulphation  is  over  discharging.  A  battery  that  is  discharged  to  a  low 
point  and  then  allowed  to  lie  around  unused  for  a  considerable  time 
would  be  destroyed  by  sulphation  or  rendered  practically  useless. 

Local  sulphation  is  caused  by  small  particles  of  the  active  materials, 
which  have  become  dislodged  from  the  plates,  catching  in  the  separators 
which  are  used  to  prevent  the  plates  from  touching  and  forming  a 
"bridge"  between  two  plates  and  discharging  them  entirely.  Sediment, 
which  gradually  accumulates  in  the  bottom  of  the  jars,  should  be  re- 
moved before  it  reaches  the  bottom  of  the  plates. 

When  the  plates  are  sulphated  the  battery  should  be  given  a  long  slow 
charge  at  one-quarter  the  normal  charging  rate,  till  the  electrolyte  shows 
the  proper  specific  gravity  and  the  voltage  has  attained  its  maximum. 
The  terminals  and  top  of  the  cell  should  be  kept  free  from  acid,  which 
will  cause  corrosion. 

Verdigris  which  forms  on  the  terminals  is  a  poor  conductor,  hence,  it 
should  be  removed  and  the  terminals  kept  bright  and  clean  to  insure  the 
proper  flow  of  the  current.  The  individual  cells  of  a  storage  battery 
should  be  tested  separately  in  order  to  determine  if  there  be  a  weak  cell 
in  the  circuit  as  such  a  cell  would  reduce  the  battery  output. 


264 


SELF-PROPELLED    VEHICLES. 


Mechanical  Generators. — The  two  methods  of  producing  A 
current  by  mechanical  means  are,  I,  by  the  use  of  dynamos,  or,  2, 
by  magnetos. 

In  any  "field"  such  as  that  produced  around  and  inside  a  coil  of  wire 
through  which  a  current  flows  or  between  the  poles  of  any  magnet  either 
electrical  or  permanent,  there  are  invisible  lines  of  force,  which  arrange 
themselves  in  a  definite  shape  around  and  between  the  poles  and  if  they 
be  cut  in  any  way  by  moving  a  wire  across  them,  a  current  is  produced 
in  the  wire  and  this  current  depends  largely  upon  the  number  of  these 
lines  of  force  which  are  cut  per  second.  It  makes  no  difference  whether 


OUT^SIJDE 
C  I  RCUIT 


FIG.  185.— CMrcuit  diagrams  to  illustrate  the  diff erence  between  a  dynamo 
and  a  magneto.     The  former   has   its   field  magnets   1< 
by    means    of   a   small    current    flowing    around   a    shunt    circuit.      In 
a    magneto    the    field    magnets    are    permanently    magnetized.      The 
strength  of  the  magnetic  field  of  a  magneto  is  constant  while  that  of 
a   dynamo    varies   with    the   output,   hence,    a  magneto    may    be   run 
at  a   widely   varying   speed   and   meet    ignition    requirements,    but  a 
dynamo  must  have  its  speed  maintained  approximately  constant 
keep  the  voltage  within  limits. 

the  wire  be  held  stationary  and  the  magnet  and  its  field  moved,  or  whether 
the  wire  itself  be  removed  and  the  field  held  stationary.  The  result  is  the 
same  so  far  as  producing  the  current  is  concerned.  The  utilization  of  this 
principle  is  the  basis  upon  which  the  mechanical  producers  of  electricity- 
dynamos  and  magnetos — are  made. 

On  account  of  the  very  general  use  of  multi-cylinder  engines  for  auto- 
mobiles a  strong  impetus  has  been  given  to  the  employment  of  mechanical 


IGNITION. 


265 


generators.  When  the  current  is  generated  by  such  means,  it  is  not 
necessary  to  be  economical  in  its  use  as  the  energy  absorbed  for  ignition 
by  a  generator  is  very  small. 

Dynamos  and  Magnetos. — A  dynamo  differs  from  a  magneto 
chiefly,  in  that  it  has  field  magnets  of  soft  iron  or  mild  steel, 
wound  with  wire  through  which  circulates  the  whole  or  a  portion 
of  the  current  generated  by  the  machine ;  a  magneto,  on  the  other 
hand,  has  field  magnets  constructed  of  steel  and  permanently 
magnetized. 


FIG.  186. — Sectional  diagram  of  the  Apple  Igniting  Dynamo.  The  parts 
shown  are:  A,  cast  iron  body  containing  the  moving  parts;  B,  th« 
hinged  lid  of  the  body;  C,  the  one  pole  piece  of  one  of  the  field 
magnets;  F,  brass  bearing  of  the  armature  spindle;  G  and  H,  fibre 
tubes  surrounding  the  spindle;  K,  brass  spider  supporting  the 
spindle;  L,  commutator;  M,  wick  feed  oil  cup;  N,  beveled  nut  sup- 
porting the  commutator;  O,  P,  Q,  supports  of  the  commutator;  R, 
the  driving  disc;  S,  lever  friction  pinion.  This  machine  can  generate 
a  direct  current  at  8  volts  at  a  speed  of  between  1,000  and  1,200 
revolutions  per  minute.  It  is  provided  with  a  simple  centrifugal 
governor  that  automatically  interrupts  the  driving  connections  when 
a  certain  speed  has  been  exceeded. 

The  circuit  diagrams,  fig.  185,  illustrate  this  difference.  In  the 
dynamos  the  field  magnets  FF  are  magnetized  by  means  of  a  small 
current  flowing  around  a  shunt  circuit ;  that  is,  a  certain  amount 
of  current  is  taken  from  the  system  and  used  to  magnetize  the 
field.  The  remainder  of  the  current  generated  is  used  in  the  out- 
side circuit. 


Dynamos. — The    field    magnets    of    a    dynamo    increase 
strength  as  the  current  which  passes  around  them  increases. 


in 


266  SELF-PROPELLED    VEHICLES. 

Moreover,  as  the  magnetic  strength  increases,  the  voltage  of  the 
generated  current  also  becomes  stronger.  Hence,  it  is  evident 
that  a  dynamo  is  not  self-regulating,  and  if  run  at  too  high  speed 
is  liable  to  be  overheated  or  even  burned  out  in  its  effort  to  fur- 
nish a  current  beyond  its  capabilities,  on  account  of  this  faculty 
of  automatically  strengthening  its  own  fields. 

Dynamos,  therefore,  cannot  be  driven  at  the  widely  varying  speeds  met 
with  in  the  operation  of  an  automobile.  They  require  to  be  driven  at  an 
approximately  uniform  speed  independent  of  the  speed  of  the  engine, 
hence  a  governor  is  necessary. 

Motion  is  imparted  to  a  dynamo  by  a  very  small  wheel  in  frictional 
contact  with  the  fly  wheel  of  the  engine.  This  frictional  wheel  is  small 
enough  to  run  the  dynamo  at  full  speed  when  the  engine  is  turned  slowly, 
as  in  cranking.  As  the  engine  speed  increases,  the  governor  acts,  and 
maintains  the  speed  of  the  dynamo  unchanged. 

A  dynamo  is  generally  used  in  connection  with  a  storage  battery  for 
ignition  purposes,  the  current  for  ignition  being  supplied  by  the  battery, 
which  in  turn  is  constantly  charged  by  the  dynamo  to  replace  the  energy 
drawn  from  the  battery  for  ignition.  An  automatic  cut  out  is  used 
which  disconnects  the  dynamo  from  the  battery  when  the  engine  stops, 
to  prevent  the  battery  from  discharging  through  the  engine.  A  voltmeter 
shows  the  condition  of  the  battery  at  all  times. 

Magnetos. — These  may  be  divided,  with  respect  to  the  man- 
ner in  which  the  current  is  generated,  into  two  types,  i,  those 
having  rotating  armatures  and  2,  those  having  stationary  arma- 
tures with  revolving  inductors.  Magnetos  may  be  further  di- 
vided with  respect  to  the  kind  of  current  generated,  into  two 
classes  I,  low  tension  and  2,  high  tension.  The  latter  class  may 
be  sub-divided  into,  I,  true  high  tension,  2,  high  tension  with  self- 
contained  coil  and,  3,  high  tension  with  separate  coil.  The  last 
two  types  are  strictly  speaking  not  high  tension  magnetos. 

Inductor  Magnetos. — In  this  class  of  magnetos  the  armature 
is  fixed  so  that  it  does  not  revolve  and  is  located  with  the  sector 
shaped  heads  of  the  core  at  right  angles  to  the  line  joining  the 
field  poles.  This  position  of  the  core  furnishes  the  least  mag- 
netically conducting  path.  An  annular  space  between  the  arma- 
ture and  the  field  poles  is  provided  for  the  rotation  of  an  inductor. 
This  consists  of  two  diametrically  opposite  cylindrical  segments 


IGNITION.  267 

of  soft  iron  supported  and  carried  by  a  shaft  located  at  the  center 
of  the  circle  described  by  the  segments. 

The  magnetic  condition  of  the  armature  core  depends  entirely 
upon  the  position  of  the  inductor.  The  latter  is  arranged,  i,  to 
revolve  continuously  with  a  gear  drive  from  the  engine  or,  2,  to 
rotate  to  and  fro  through  a  small  arc  by  link  connection  to  the 
half  time  shaft.  An  example  of  this  type  is  shown  in  fig.  194  and 
later  described  in  the  paragraph  on  "Ignition  with  inductor  mag- 
neto." 

Low  Tension  Magnetos. — Generators  of  this  class  may  be 
used  to  supply  a  current  of  low  voltage  for,  I,  make  and  break 
ignition  or  for,  2,  high  tension  ignition  with  induction  coils  or  coil 
spark  plugs.  A  low  tension  magneto  has  an  armature  winding 
consisting  of  about  150  to  200  turns  of  fairly  thick  wire,  covered 
with  a  double  layer  of  insulating  material. 

One  end  of  the  winding  is  grounded  to  the  armature  core  and  the 
other,  brought  to  a  single  insulated  terminal.  When  this  terminal  is  con- 
nected to  any  metal  part  of  the  magneto  or  engine  (since  the  latter  is 
in  metallic  contact  with  the  base  of  the  magneto),  the  circuit  is  complete. 
The  wiring  therefore  is  very  simple,  which  is  one  of  the  advantages  of 
the  system. 

The  "live  end"  of  the  armature  winding  is  brought  out  by  means  of  a 
metallic  rod  passing  lengthways  through  the  shaft  of  the  armature;  a 
hard  rubber  bushing  is  provided  as  insulation  between  the  shaft  and  the 
rod.  The  live  end  of  the  winding  is  located  at  one  end  of  the  armature 
shaft,  from  which  the  current  flows  to  an  insulated  terminal  by  means  of 
a  metal  contact  which  is  pressed  against  the  revolving  rod  by  a  spring. 

High  Tension  Magnetos. — The  term  high  tension,  as  applied 
to  magnetos,  by  popular  usage,  includes  all  magnetos  which  de- 
liver a  high  tension  current  at  their  terminals. 

They  may  be  divided  into  three  distinct  classes :  I,  those  in  which 
the  induction  secondary  wiring  is  wound  directly  on  the  armature ; 
2,  those  having  a  secondary  induction  coil  contained  within  the 
magneto,  and  3,  those  having  the  coil  in  a  separate  box  usually 
placed  on  the  dash. 


268  SELF-PROPELLED     VEHICLES. 

A  high  tension  magneto  of  the  second  or  third  class  is  quite 
similar  to  the  low  tension  type  in  that  it  generates  a  low  tension 
current.  This  does  not,  however,  pass  directly  to  the  cylinders, 
but  instead,  delivers  the  current  to  a  secondary  induction  coil 
which  consists  of  I,  a  primary  winding  of  a  few  turns  of  heavy 
insulated  wire  to  which  the  low  tension  current  is  delivered  and 
2,  a  secondary  winding  surrounding  the  primary,  and  consisting  t 
of  many  turns  of  very  fine  insulated  wire.  The  passage  of  the 
low  tension  current  through  the  primary  induces  a  high  tension 
current  in  the  secondary.  This  induced  current  has  pressure 
enough  to  bridge  the  gap  between  the  terminals  of  the  spark  plug. 

A  condenser  is  also  inserted  in  the  circuit  to  still  further  in- 
crease the  tension  of  the  induced  current  at  the  instant  of  spark- 
ing. 

The  current  used  for  sparking  must  be  delivered  to  the  various 
cylinders  in  proper  sequence.  This  is  accomplished  by  a  self  con- 
tained timing  device  consisting  of  as  many  stationary  contacts  as 
there  are  cylinders,  each  connected  by  a  cable  to  its  cylinder  spark 
plug.  A  rotary  brush  successively  delivers  current  to  each  of 
these  contacts. 

Fig.  187  is  a  circuit  diagram  of  a  high  tension  magneto  with  a 
self-contained  induction  coil.  A  low  tension  current  is  generated 
in  the  winding  A  of  the  armature,  which  is  rotated  between  two 
powerful  and  permanent  magnets.  The  current  flowing  from 
the  armature  is  an  alternating  one  having  two  points  of  maximum 
density  in  each  armature  revolution. 

As  the  current  leaves  the  armature,  it  is  offered  two  paths,  i, 
the  shorter  through  the  interrupter  U  to  ground  and  2,  the  longer 
through  the  primary  P  of  the  induction  coil  to  ground.  A  third 
path  through  the  condenser  K  is  only  apparently  available ;  it  is 
obstructed  by  the  refusal  of  the  condenser  to  permit  the  passage 
of  the  current  as  the  condenser  will  merely  absorb  a  certain 
amount  of  current  at  the  proper  moment,  that  is  at  the  instant  of 


IGNITION. 


269 


the  opening  of  the  interrupter.  The  interrupter  being  closed  the 
greater  part  of  the  time,  allows  the  primary  current  to  avail  itself 
of  the  short  path  it  offers.  At  the  instant  at  which  the  greatest 
current  intensity  exists  in  the  armature,  the  interrupter  is  opened 
mechanically,  so  that  the  primary  current  has  no  choice  but  must 
take  the  path  through  the  primary  P  of  the  induction  coil.  A 


: i 


PRIMARY  CIRCUIT 

SECONDARY  CIRCUIT 

GROUND  CIRCUIT  THROUGH  FRAME 


Fie.  187. — Circuit  diagram  of  a  high  tension  magneto.  A  is  the  armature 
winding;  P,  primary  of  transformer;  S,  secondary  of  transformer; 
D,  distributing  brush  carrier;  E,-  contact  segments;  F,  safety  spark 
gap;  G,  terminals  to  plugs;  U,  interrupter;  Z,  spark  plugs.  The 
principles  of  operation  are  described  in  the  text. 

certain  amount  of  current  is  at  this  instant  also  absorbed  by  the 
condenser  K.  This  sudden  rush  of  current  into  the  primary  P  of 
the  induction  coil,  induces  a  high  tension  current  in  the  secondary 
winding  S  of  the  coil  which  has  sufficient  pressure  to  bridge  the 
air  gap  of  the  spark  plug. 


270 


SELF-PROPELLED     VEHICLES. 


The  sharper  the  rush  of  current  into  the  primary  winding  P, 
the  more  easily  will  the  necessary  intensity  of  current  for  a  jump 
spark  be  induced  in  the  secondary  winding  S. 

The  distribution  of  the  current  in  proper  sequence  to  the  vari- 
ous engine  cylinders  is  accomplished  as  follows :  the  high  tension 
current  induced  in  the  secondary  S  of  the  induction  coil  is  de- 
livered to  a  distributing  brush  carrier  D  that  rotates  in  the  mag- 
neto at  the  same  speed  as  the  crank  shaft  of  the  engine.  This 
brush  carrier  slides  over  insulated  metal  segments  E — there  be- 
ing one  for  each  cylinder.  Each  of  these  segments  E  connects 


M 


FIG.  188. — The  Eisemann  high  tension  magneto  with  coil  in  a  separate 
box.  Five  terminals  are  shown  in  the  end  view;  the  central  one  is 
connected  to  the  coil  and  the  other  four  to  the  spark  plugs.  The 
two  views  show  the  parts  as  follows:  A,  cam  nut;  B,  steel  contact 
for  high  tension  distributer;  C,  platinum  contact  for  make  and  break 
lever;  D,  high  tension  distributer  cover;  E,  nut  for  adjustable  con- 
tact screw;  P.  spring  for  make  and  break  lever;  G,  carbon  contact 
for  high  tension  distributer;  H,  make  and  break  lever;  I,  low  ten- 
sion carbon  brush;  K,  adjustable  platinum  contact  screw;  L,  grease 
box  for  large  toothed  wheel;  M,  nut;  N,  cam;  O,  cable  joints;  P, 
distributer  plate;  Q,  metal  contact;  S,  screw  for  spring  for  make 
and  break  lever;  V,  high  tension  distributer. 

with  one  of  the  terminal  sockets  that  are  connected  by  cable  with 
the  spark  plugs  as  shown.  At  the  instant  of  interruption  of  the 
primary  current,  the  distributing  brush  is  in  contact  with  one  of 


IGNITION. 


271 


the  metal  segments  E  and  so  completes  a  current  to  that  spark 
plug  connected  with  this  segment. 

Should  the/  circuit  between  the  terminal  G  and  its  spark  plug- 
be  broken,  or  the  resistance  of  the  spark  plug  be  too  great  to  per- 
mit a  spark  to  jump,  then  the  current  might  rise  to  an  intensity 
sufficient  to  destroy  the  induction  coil.  To  prevent  this,  what  is 
known  as  a  safety  spark  gap  F  is  introduced.  This  will  allow 


FIG.  189. — The  Komet  Magneto.  The  armature  Is  speeded  the  same  as  the 
crank  shaft  for  a  four  cylinder  engine,  and  for  a  three  or  six  cylinder 
engine  the  armature  runs  ft  or  1J4  times  the  crank  shaft  speed, 
respectively.  The  parts  of  this  magneto  are  as  follows:  1,  brass 
plate;  2,  brass  stud;  3,  contact  piece;  4,  platinum  contact  screw;  5, 
hard  rubber  disc;  6,  hard  rubber  bushing;  7.  interrupter  spring;  8, 
platinum  point;  9,  interrupter  disc;  10,  condenser;  11,  slide  ring; 
12,  carbon  brush;  13,  carbon  spring;  14,  hard  rubber  carbon  holder; 
15,  brass  piece;  16,  hard  rubber  cup;  17,  carbon;  18,  conductor  of 
distributer;  19,  hard  rubber  tube;  20,  distributer  disc;  21.  distributer 
gear;  22,  gear  on  armature;  23,  high  tension  terminals;  24,  timing 
lever;  25,  spring  to  armature  cover;  26,  armature  cover;  27,  safety 
air  gap;  28,  distributer  cover;  29,  screw;  30,  bracket;  31,  brass 
cover;  22,  spring;  33,  fibre  ring. 


272  SELF-PROPELLED     VEHICLES. 

the  current  to  rise  only  to  a  certain  maximum,  after  which  dis- 
charges will  take  place  through  this  gap  F.  In  construction  the 
spark  discharges  over  this  gap  are  visible  through  a  small  glass 
window  conveniently  located. 

Synchronous  Drive. — For  ignition  purposes,  magnetos  are 
generally  constructed  to  deliver  an  alternating  current,  that  is,  a 
current  consisting  of  a  succession  of  regularly  alternating  electri- 
cal impulses,  varying  in  intensity  from  a  plus  maximum  to  a  neg- 
ative maximum  and  separated  by  points  of  zero  pressure  depend- 
ent upon  the  armature  position  with  respect  to  the  field.  Hence, 
it  is  necessary  that  the  generator,  unless  it  run  at  high  speed, 
should  be  driven  synchronously,  that  is,  at  a  speed  in  a  definite 
rate  to  that  of  the  engine  in  order  that  the  periods  when  a  spark 
is  desired  shall  coincide  with  the  periods  when  sufficient  voltage 
is  being  developed,  as  otherwise  the  sparking  periods  might  occur 
with  a  zero  point  of  electrical  generation  and  no  spark  would  be 
produced. 

To  meet  these  conditions  the  drive  must  be  positive  and  may 
consist  of  either  toothed  wheel  gears  or  chain  and  sprocket ;  the 
former  is  more  desirable  since,  with  a  chain  and  sprocket  drive, 
there  is  sufficient  -lost  motion  when  the  chain  is  loose  enough  for 
smooth  running,  to  prevent  the  accurate  timing  of  the  spark. 

The  friction  gear  drive  or  belt  and  pulley  are  alike  objection- 
able, from  the  fact  that  no  slipping  or  variation  is  permissible. 
While  some  recent  forms  of  h'igh  tension  magneto  are  advertised 
to  operate  asynchonously,  that  is,  not  speeded  in  definite  ratio 
to  the  engine,  the  common  types  are  so  made  that  the  spark  shall 
occur  in  the  first  cylinder  at  precisely  the  moment  the  magneto 
armature  is  at  a  certain  point  in  its  rotation.  If,  therefore,  this 
condition  be  not  strictly  observed,  the  spark  will  be  of  defective 
intensity,  and  the  control  of  the  engine  complicated. 


IGNITION. 


273 


Ignition  Systems. — There  are  two  systems  in  general  use  for 
igniting  the  charge  by  electricity : 

1.  The  low  tension  or  make  and  break. 

2.  The  high  tension  or  jump  spark. 

The  low  tension  system  is  electrically  simple  and  mechanically 
complex,  while  the  high  tension  system  is  electrically  complicated 
and  mechanically  simple. 


FIG.  190. — Plan  view  of  the  Ford  combined  fly  wheel,  magneto  and 
planetary  change  gear.  The  magneto  consists  of  a  stationary  spider, 
shown  at  the  left,  which  carries  32  coils  in  which  the  currents  are 
generated  and  a  series  of  permanent  revolving  magnets  attached  to 
the  fly  wheel,  the  combination  producing  a  low  tension  current  which 
is  used  in  the  ordinary  manner  with  coils,  timer  and  spark  plugs. 

Low  Tension  Ignition. — In  this  system  there  is  a  device 
known  as  an  igniter,  placed  in  the  combustion  space  of  the  en- 
gine cylinder.  This  consists  of  two  electrodes,  one  of  which  is 
stationary  and  the  other  movable.  The  stationary  electrode  is 
insulated,  while  the  other  having  an  arm  within  the  cylinder  and 
placed  conveniently  near  is  capable  of  being  moved  from  the  out- 


274  SELF-PROPELLED    VEHICLES. 

side  so  that  the  arm  comes  into  contact  with  the  stationary  elec- 
trode and  separates  from  the  latter  with  great  rapidity.  This 
sudden  breaking  of  the  circuit  produces  an  electric  arc  or  primary 
spark  caused  by  the  inductance — that  is,  by  the  "inertia"  or 
tendency  of  the  current  to  continue  flowing  after  the  separation 
of  the  contact  points. 

The  current  may  be  derived  from  either  a  primary  battery, 
storage  battery  or  low  tension  magneto. 

While  it  is  possible  to  produce  a  spark  by  simply  breaking  a  battery 
circuit,  it  is  necessary  in  order  to  have  a  spark  of  sufficient  intensity 
and  duration  to  introduce  into  the  circuit  a  primary  induction  coil — this 
is  described  in  a  later  section.  When  a  magneto  is  used,  the  coil  is  not 
necessary  as  the  armature  winding  serves  the  same  purpose.  A  magneto 
furnishing  either  direct  or  alternating  current  may  be  used ;  the  voltage 
will  depend  on  the  armature  speed  and  the  strength  of  the  magnets. 

Iridium  or  platinum  is  used  for  contact  points  of  the  electrodes,  as 
these  metals  resist  the  oxidizing  effect  of  electricity  and  heat  better  than 
others. 

In  low  tension  ignition  a  considerable  interval  of  time  is  required  for 
the  current  to  rise  to  its  full  value  and  the  time  of  separation  of  the 
electrodes  should  not  be  sooner  than  the  moment  when  the  maximum  cur- 
rent strength  has  been  attained.  When  a  magneto  is  used  the  current 
strength  increases  with  the  speed,  hence  the  contact  interval  can  be  shorter 
at  high  speeds  than  when  a  battery  is  used. 

Primary  Induction  Coils. — When  an  electric  current  flows 
along  a  coiled  conductor,  a  counter  current  is  induced  which  op- 
poses any  rapid  change  in  the  current  strength.  This  principle 
is  employed  in  low  tension  ignition  to  intensify  the  spark  when  a 
battery  forms  the  current  source.  The  device  which  accom- 
plishes this  effect  is  known  as  a  primary  induction  coil  and  con- 
sists of  a  long  iron  core  wound  with  a  considerable  length  of 
low  resistance  copper  wire,  the  length  of  the  core  and  the  num- 
ber of  turns  of  the  insulated  winding  determining  the  efficiency. 
The  current  passing  through  the  winding  magnetizes  the  soft 
iron,  and  a  self-induced  current  is  generated.  As  soon  as  the 
circuit  is  broken,  the  magnetic  reactance  tends  to  continue  the 
flow  of  current,  despite  the  break  in  the  circuit,  and  occasions  a 
spark  of  great  heat  and  brilliancy.  The  spark  occurs  at  the 
moment  of  breaking  the  circuit,  not  at  the  moment  of  making. 


IGNITION.  275 

The  Low  Tension  Circuit. — The  elements  which  compose  a 
low  tension  or  make  and  break  circuit  are  as  follows : 

1.  A  source  of  current  supply  consisting  of  either  a  primary 
battery,  accumulator  or  low  tension  magneto. 

2.  A  primary  induction  coil  when  a  battery  is  used. 

3.  An  igniter. 

4.  A  switch  for  breaking  the  circuit,  and  an  additional  switch 
to  alternate  between  the  battery  and  the  magneto  when  both 
means  of  furnishing  the  current  are  provided. 

5.  Connecting  conductors. 

Fig.  191  shows  a  low  tension  system  of  a  two  cylinder  engine 
having  all  the  above  elements. 

Two  sources  of  current  supply  are  provided — a  dry  battery  and  a 
magneto.  One  terminal  of  both  the  battery  and  magneto  is  grounded; 
the  other  terminal  A  of  the  magneto  M  is  connected  to  the  point  S  of  a 
threeway  switch.  The  cells  comprising  the  battery  J  are  connected  in 
series  and  the  terminal  not  grounded  is  connected  to  a  primary  induction 
coil  K  and  thence  to  the  point  T  of  the  threeway  switch.  By  moving 
the  arm  of  this  switch  to  the  right  or  left,  current  may  be  had  from 
the  battery  or  magneto  respectively.  A  conductor  C  connects  the  third 
point  of  the  switch  to  the  stationary  or  insulated  electrode  of  each  igni- 
ter, a  single  throw  switch  being  placed  at  each  igniter  which  allows  either 
or  both  cylinders  to  be  thrown  out  of  the  circuit  at  will.  The  movable 
electrodes  and  metal  of  the  engine  furnishes  the  ground  return  to  the 
battery  and  magneto. 

On  a  multi-cylinder  engine  it  is  evident  that  no  other  contact  can  be 
made  at  the  moment  of  break  in  one  cylinder  since  the  current  would 
then  flow  through  any  other  igniter  that  might  be  in  contact  instead  of 
producing  a  spark  at  the  break. 

The  operation  of  the  make  and  break  system  is  as  follows :  Starting, 
say  on  the  battery,  the  arm  of  the  threeway  switch  is  turned  upon  point 
T.  The  movable  electrode  D  of  the  first  cylinder  being  in  contact  with 
the  insulated  electrode  B  by  the  spring  E,  the  current  will  flow  from 
the  battery  J  through  the  coil  K,  thence  through  the  threeway  switch  and 
the  single  throw  switch  to  the  insulated  electrode  B.  The  movable  elec- 
trode D  being  in  contact  with  the  insulated  electrode  B,  the  current  re- 
turns to  the  battery  through  D  and  the  metal  of  the  engine,  thus  com- 
pleting the  circuit.  As  the  cam  G  revolves  in  the  direction  indicated  by 
the  arrow,  the  rod  F  rises,  which  allows  spring  E  to  bring  the  movable 
electrode  D  into  contact  with  the  insulated  electrode  B,  thus  completing 
the  circuit  previously  described.  When  the  nose  of  cam  G  passes  from 
under  the  lower  end  of  F,  the  latter  drops  with  great  rapidity  by  the 
action  of  spring  H  and  in  so  doing  a  shoulder  at  the  upper  end  of  F 
strikes  the  external  arm  of  D  a  blow  causing  the  contact  point  of  D  to  be 
snapped  apart  from  B.  This  cycle  of  operations  is  repeated  by  the 
ignition  mechanism  of  each  cylinder  in  rotation. 

• 


276 


SELF-PROPELLED     VEHICLES. 


At  the  instant  the  circuit  is  broken  by  the  separation  of  the  contact 
points,  the  counter  current  induced  in  the  coil  K  opposes  any  rapid 
change  in  the  current  strength,  hence,  the  current  continues  to  flow 
momentarily  after  the  circuit  is  broken  resulting  in  a  primary  spark.  The 
action  is  the  same  as  though  the  current  possessed  the  property  of 
"inertia,"  that  is,  time  and  resistance,  both  are  necessary  to  bring  it  to  a 
state  of  rest.  This  inertia  effect  is  intensified  by  the  action  of  the  in- 
duction coil.  When  a  magneto  is  used  the  armature  windings  serve  the 
same  purpose. 

The  timing  of  the  spark  is  accomplished  by  the  adjustable  guides  L 
which  serve  to  vary  the  horizontal  position  of  the  lower  ends  of  the  rods 
F  and  thus  vary  the  instant  at  which  their  ends  pass  the  nose  of  each 
cam. 

In  make  and  break  ignition  it  is  necessary  in  order  to  produce 
a  good  spark,  that  the  "break"  or  separation  of  the  contact  points 


FIG.  191. — A  low  tension  or  make  and  break  ignition  system.  In  operation, 
as  the  nose  of  the  cam  G  passes  rod  F,  the  latter  suddenly  drops  by 
the  action  of  spring  H.  The  head  of  the  rod,  which  has  been  raised 
by  the  cam  somewhat  above  the  arm  of  D,  will  in  its  descent  strike 
D  a  blow  which  abruptly  breaks  contact  between  D  and  B,  thus 
producing  a  spark.  When  not  acted  upon  by  the  head  of  the  rod 
F,  D  is  held  in  contact  with  B  by  the  Spring  B.  The  system  is 
explained  in  detail  in  the  text. 

of  the  igniter  should  take  place  with  extreme  rapidity,  that  is, 
the  spring  H  should  be  sufficiently  strong  to  cause  the  shoulder 
or  rod  F,  when  it  falls,  to  strike  the  igniter  arm  a  decided  blow, 
thus  quickly  snapping  apart  the  contact  points. 


IGNITION. 


277 


Magnetic  Spark  Plugs. — The  electrical  advantages  of  low 
tension  ignition  are  somewhat  offset  by  the  mechanical  compli- 
cation necessary  to  operate  the  igniter.  In  order  to  simplify  the 
mechanism,  a  method  has  been  devised  for  operating  the  elec- 
trodes of  the  igniter  by  magnetism.  This  is  accomplished  by  a 
device  known  as  a  magnetic  spark  plug  illustrated  in  fig.  192.  A 
list  of  the  parts  is  given  under  the  figure. 


PIG.  192. — The  Bosh  magnetic  spark  plug.  This  consists  of  a  coil  A 
having  one  end  connected  to  a  terminal  B.  and  the  other  to  the  plug 
casing  C.  A  spark  is  produced  when  a  separation  takes  place  be- 
tween the  moving  contact  D  and  the  stationary  contact  E.  Within 
the  plug  is  a  metal  core  F  and  a  swinging  lever  G,  which  lever 
pivots  on  the  projection  H  which  is  a  part  of  the  core  F.  K  shows 
a  portion  of  a  hair-pin  spring,  the  end  L  01  which  rests  in  a  recess 
within  the  lever  G,  the  ordinary  tension  of  the  spring  tending  to  hold 
the  lower  end  of  the  lever  G  carrying  the  contact  D  against  the 
stationary  contact  piece  E. 


278 


SELF-PROPELLED    VEHICLES. 


The  operation  of  the  plug  is  as  follows :  when  the  timing  de- 
vice on  the  low  tension  magneto  forms  a  contract  for  giving  a 
spark  to  any  cylinder,  the  circuit  through  the  plug  is  through 
terminal  B  and  the  coil  A,  thence  through  C  and  back  to  the  en- 
gine. 

The  completion  of  this  circuit  energizes  the  core  F  which  tends  to  pull 
the  upper  end  M  of  the  lever  G  towards  the  right,  but  it  is  protected 
from  contact  with  the  core  by  the  non-magnetic  brass  plug  N.  The  pull- 
ing of  the  upper  end  of  the  lever  G  to  the  right  carries  the  lower  end  to 
the  left,  separating  it 'from  the  stationary  contact  E,  thereby  breaking  the 
circuit.  Immediately  the  circuit  is  broken  the  coil  A  surrenders  its  elec- 
tro-magnetic power,  the  core  F  is  demagnetized  and  the  end  of  the  hair-pin 
spring  L  forces  the  lower  end  of  the  lever  G  to  the  right,  as  the  spring 
L  exerts  its  pressure  beneath  the  fulcrum  H  and  which  brings  the  con- 
tacts D  and  E  together. 


PIG.  193. — Wiring-  diagram  of  a  low  tension  system  with  magnetic  spark 
plugs.  A  portion  of  the  wiring  of  the  magneto  armature  is  short 
circuited  by  the  platinum  points  of  the  interrupter,  and  when  the 
circuit  is  broken,  the  resulting  armature  reaction  has  the  effect  of 
raising-  the  armature  voltage  sufficiently  to  operate  the  plugs. 

At  the  bottom  of  the  contact  piece  there  is  an  insulated  fixed  stem  which 
is  magnetically  divided  in  about  the  middle  by  means  of  a  brass  part,  so 
that  when  the  current  passes  through  the  coil  A  only  the  portion  of  the 
stem  above  the  brass  part  can  be  magnetized  and,  as  a  result  of  this 
magnetization  the  upper  end  M  of  the  interrupter  lever  G,  which  directly 
faces  the  magnetized  part,  is  attracted,  the  lower  end  D  simultaneously 
breaking  contact  with  the  contact  piece  E,  thus  interrupting  the  current 
and  producing  a  spark.  In  the  normal  position  of  the  interrupter  lever 
G,  the  lower  end  presses  against  the  contact  piece  E,  being  kept  in  that 
position  by  the  horseshoe  shaped  spring  K,  which  passes  right  over  the 
top  of  the  stem  and  lies  in  slots  in  the  sides. 

The  top  of  the  coil  is  fitted  with  a  terminal  screw  to  which  the  current 


IGNITION. 


279 


from  the  magneto  is  led.  Current  may  also  be  taken  from  a  primary  or 
secondary  battery.  In  this  case  a  timer  on  the  engine  is  necessary  to 
distribute  the  current  to  the  cylinders  in  proper  sequence. 

Fig.  193  shows  the  magnetic  spark  plug  connections  for  a  four 
cylinder  engine.  The  current  is  supplied  by  a  low  tension  mag- 
neto. 

A  portion  of  the  wiring  of  the  armature  is  short  circuited  by  the  plat- 
inum points  of  the  interrupter,  and  when  the  circuit  is  interrupted,  the 
resulting  armature  reaction  has  the  effect  of  raising  the  voltage  of  the 
armature  sufficiently  to  operate  the  magnetic  plugs.  The  rotating  dis- 
tributing bar  is  adjusted  in  such  a  way  that  it  is  always  in  connection  with 


FIG.  194. — A  low  tension  ignition  system  with  an  inductor  magneto  of  the 
oscillating-  type.  The  inductor  E  is  rotated  to  and  fro  by  means  of 
a  link  R,  one  end  of  which  is  attached  to  the  inductor  crank,  and  the 
other  to  the  igniter  cam  C.  Two  views  are  shown:  immediately  be- 
fore and  after  sparking.  S  is  the  grounded  electrode  of  the  igniter; 
T  an  adjustable  hammer  which  is  secured  in  position  by  a  lock  nut  N. 

one  of  the  spark  plugs  at  the  moment  when  the  contact  breaker  of  the 
magneto  interrupts  the  circuit,  so  that  the  circuit  to  the  plugs  is  closed 
and  these  are  magnetized  for  operation. 

The  spark  is  advanced  or  retarded  by  rotating  the  timing  lever,  in  the 
same  manner  as  with  a  high  tension  magneto,  and  the  timing  range  cor- 
responds to  an  angle  of  50  degrees  on  the  armature  shaft.  The  magneto 
is  switched  off  in  the  same  manner  as  a  high  tension  magneto,  by  mak- 
ing a  ground  connection.  This  is  done  by  small  plug  switches  with  either 
a  single  plug  or  with  a  number  of  plugs  equal  to  the  number  of  cylin- 
ders, to  enable  each  cylinder  to  be  switched  out  separately  for  testing 
purposes,  from  the  seat  while  the  car  is  in  motion. 


280  SELF-PROPELLED    VEHICLES. 

Ignition  with  Inductor  Magneto. — In  this  system  of  low  ten- 
sion ignition,  the  current  is  furnished  by  a  magneto  having 
a  stationary  armature  and  a  rotating  inductor  as  before  described. 
The  inductor  is  arranged  to  either  revolve  continuously  or  to  os- 
cillate through  a  small  arc.  An  example  of  the  latter  type  is 
shown  in  fig.  194  which  illustrates  the  Simms-Bosch  System. 

In  the  figure,  the  mechanism  is  shown  in  two  positions — immediately 
before  and  after  sparking.  The  cam  which  operates  the  make  and  break 
igniter  has  a  link  connection  to  the  inductor  crank  of  the  magneto  which 
gives  an  oscillating  motion  to  the  inductor.  The  connection  is  such  that 
at  the  instant  of  "break"  the  inductor  cuts  through  the  greatest  number 
of  magnetic  lines. 

The  cam  C,  on  the  half  time  shaft,  makes  a  contact  just  before  spark- 
ing, and  immediately  breaks  it  again  by  permitting  the  hammer  T  to  fall 
on  the  cam  S.  A  spark  is  produced  at  the  instant  of  break  of  contact 
at  N. 

The  winding  of  the  armature  A  has  one  end  grounded  through  the 
base  of  the  magneto,  the  current  returning  through  the  engine  to  the 
point  S ;  the  other  end  of  the  winding  is  led  through  an  insulated  post 
to  the  nut  N  by  which  it  is  connected  with  a  stud  brought  through  the 
cylinder  wall,  where  a  wiper,  indicated  by  dotted  outline,  normally  rests 
against  it  by  means  of  a  spring. 

High  Tension  Ignition. — In  this  method  of  producing  a 
spark,  a  device  called  a  spark  plug  is  employed.  This  consists 
of  two  stationary  electrodes,  one  of  which  is  grounded  to  the  en- 
gine cylinder  and  the  other  insulated.  The  points  of  the  elec- 
trodes are  permanently  separated  from  each  other  by  about  1/32 
of  an  inch,  the  space  between  the  points  being  known  as  an  air 
gap.  This  space  offers  so  much  resistance  to  the  flow  of  an 
electric  current  that  a  very  high  pressure  is  required  to  cause  the 
current  to  burst  through  the  air  gap  and  produce  a  spark,  hence 
the  term  "high  tension  ignition." 

Since  '.he- spark  jumps  from  one  electrode  to  the  other,  this 
method  of  igniting  the  charge  is  also  known  as  the  jump  spark 
system.  The  spark  itself  is  properly  described  by  the  prefix 
high  tension  or  secondary. 

In  the  production  of  the  spark  two  distinct  circuits  are  necessary,  I,,  a 
low  tension  or  primary  circuit  and  2,  a  high  tension  or  secondary  cir- 
cuit. The  current  which  Hows  through  the  low  tension  circuit  is  called 
the  primary  current  and  that  which  it  induces  in  the  high  tension  circuit, 
the  secondary  current. 


IGNITIOtf.  281 

In  order  to  obtain  the  high  pressure  required  to  produce  a  spark,  a 
device  known  as  a  secondary  induction  coil  is  used  which  transforms  the 
primary  current  of  low  voltage  and  high  amperage  into  a  secondary  cur- 
rent of  high  voltage  and  low  amperage,  that  is,  the  quantity  of  the  cur- 
rent is  decreased  and  its  pressure  increased. 

The  general  principles  upon  which  high  tension  or  jump  spark  ignition 
is  based  are  as  follows : 

An  automatic  device  is  placed  in  the  primary  circuit  which  closes  and 
opens  it  at  the  time  a  spark  is  required.  When  the  circuit  is  closed,  the 
primary  current  flows  through  the  primary  winding  of  the  coil  and  causes 
a  secondary  current  to  be  induced  in  the  secondary  winding.  The  spark 
plug  being  included  in  the  secondary  circuit  opposes  the  flow  of  the 
current  by  the  high  resistance  of  its  air  gap.  Since  the  pressure  of  the 
secondary  current  is  sufficient  to  overcome  this  resistance,  it  flows  or 
"jumps"  across  the  gap  and  in  so  doing  intense  heat  is  produced  result- 
ing in  a  spark. 

Sometimes  the  spark  is  obtained  by  keeping  the  primary  circuit  closed 
except  during  the  brief  interval  necessary  for  the  passage  of  the  spark 
at  the  plug  points.  A  secondary  spark,  then,  may  be  produced  by  either 
open  or  closed  circuit  working,  that  is,  the  primary  circuit  may  be  kept 
either  opened  or  closed  during  the  intervals  between  sparks. 

The  automatic  device  which  controls  the  primary  current  to  produce  a 
spark  by  the  first  method  is  called  a  contact  maker  and  by  the  second 
method,  a  contact  breaker.  A  closed  primary  circuit  with  a  contact  breaker 
is  used  to  advantage  on  small  engines  run  at  very  high  speed  as  it  allows 
time  for  the  magnetism  or  magnetic  flux  in  the  core  of  the  coil  to  attain 
a  density  sufficient  to  produce  a  good  spark.  The  word  timer  is  usually 
applied  to  any  device  which  controls  the  primary  current,  when  it  con- 
trols both  the  primary  and  secondary  currents,  as  in  synchronous  ignition 
it  is  called  a  distributer.  Before  explaining  the  different  systems  of  high 
tension  ignition  the  several  devices  used,  such  as  induction  coils,  spark 
plugs,  etc.,  will  be  described  in  some  detail. 

Secondary  Induction  Coils. — In  order  to  obtain  the  high 
voltage  necessary  to  produce  a  secondary  spark,  a  device  called 
a  secondary  induction  coil  is  used.  This  transforms  the  primary 
low  tension  current  into  a  secondary  high  tension  current. 
There  are  two  varieties  of  these  coils: 

1.  Plain  or  non-vibrator  coil. 

2.  Vibrator  coil. 

A  plain  or  single  spark  coil  consists  of  three  parts,  I,  an  iron  core,  2, 
a  primary  winding  and  3,  a  secondary  winding. 

The  core  of  the  coil  consists  of  a  bundle  of  soft  iron  wires,  about  six 
or  seven  inches  long  and  in  sufficient  number  to  make  the  diameter  of 
the  core  about  three  quarters  of  an  inch.  The  reason  that  a  bundle  of 
wires  is  used  for  the  core  instead  of  a  solid  rod  is  that  the  wire  core 
can  be  more  rapidly  magnetized  and  demagnetized.  The  core  is  covered 
with  an  insulation  of  paper,  vulcanite  or  other  material,  around  which  is 


282 


SELF-PROPELLED     VEHICLES. 


wound  the  primary  coil  which  consists  of  two  or  three  layers  of  coarse 
insulated  wire.  Sometimes  a  light  insulation  is  placed  over  the  primary 
winding,  around  which  is  wound  the  secondary  coil  consisting  of  from 
ten  thousand  to  fifteen  thousand  turns  of  very  fine  wire  insulated  by  a 
silk  covering.  It  is  usual  to  place  between  each  layer  of  the  secondary 
winding,  a  layer  of  paraffined  paper.  This  insures  the  insulation. 

The  coil  is  placed  in  a  neat  and  substantial  box  and  the  terminals  of 
the  windings  are  connected  to  binding  posts  placed  on  the  outside. 

The  operation  of  the  coil  is  as  follows:  when  an  electric  current  is 
passed  through  the  primary  winding,  it  magnetizes  the  core  which  pro- 
duces a  magnetic  field  in  the  surrounding  space.  Any  increase  or  de- 
crease of  current  in  the  primary  winding  induces  a  current  in  the  sec- 
ondary winding;  this  induced  current  lasts  only  during  the  time  of  tn- 
crease  or  decrease  of  the  primary  current. 

Now,  the  pressure  of  the  current  induced  in  the  secondary  circuit  de- 
pends upon  the  ratio  between  the  number  of  turns  of  the  two  windings, 


FIG.  195. — Diagram  of  a  vibrator  coil.  The  parts  are  as  follows:  A,  con- 
tact screw;  B,  battery;  C,  core;  D,  vibrator  terminal;  G,  condenser: 
P,  primary  winding;  S,  secondary  winding;  W,  switch;  Y,  vibrator. 
When  the  switch  is  closed,  the  following  cycle  of  actions  take  place: 
(a)  the  primary  current  flows  and  magnetizes  core;  (b)  magnetized 
core  attracts  the  vibrator  and  breaks  primary  circuit;  (c)  the 
magnetism  vanishes,  inducing  a  momentary  high  tension  current  in 
the  secondary  winding;  (d)  magnetic  attraction  of  the  core  having 
ceased,  vibrator  spring  re-establishes  contact;  (e)  primary  circuit 
is  again  completed  and  the  cycle  begins  anew. 

upon  the  sizes  of  wires  used  and  also  upon  the  rate  of  variation  of  the 
current  strength  in  the  primary  circuit.  For  instance,  if  the  primary 
winding  contains  one  hundred  turns  and  the  secondary  ten  thousand 
turns,  the  voltage  of  the  secondary  circuit  will  be  nearly  one  hundred 
times  that  of  the  primary. 

In  a  plain  coil  the  primary  current  is  made  and  broken  once  for  each 
Spark  by  a  timing  device  on  the  engine,    At  every  "make"  the  field  of 


IGNITION.  283 

force  of  each  turn  in  the  coil  grows  rapidly,  and  cuts  the  neighboring 
turns,  inducing  an  electromotive  force  that  opposes  the  increase  of  the 
current.  On  the  other  hand,  at  every  "break,"  the  primary  field  rapidly 
vanishes,  the  lines  again  cutting  the  turns,  but  in  a  manner  that  tends 
to  oppose  the  decrease  of  the  current. 

This  opposition  to  any  rapid  change  in  the  current  strength  is  called 
self-induction.  The  current  which  produces  the  spark  occurs  at  the  time 
of  break  and  since  the  strength  of  this  current  depends  upon  the  rapidity 
with  which  the  strength  of  the  primary  current  falls  a  timing  device  is 
used,  which  is  so  constructed  that  the  break  will  occur  very  abruptly. 

The  view  has  been  held  by  some  that  a  series  of  sparks  occurring  with 
great  rapidity  is  more  effective  for  ignition  than  the  single  spark  pro- 
duced by  the  plain  coil.  This  led  to  the  development  and  use  of  the 
vibrator  coil,  though  opinion  differs  as  to  the  relative  merits  of  the  two 
systems. 

A  vibrator  coil  contains  in  addition  to  the  two  windings  of  the  plain 
coil,  a  magnetic  vibrator  and  a  condenser.  The  object  of  the  vibrator  is 
to  rapidly  make  and  break  the  primary  circuit  during  the  time  in  which 
the  battery  is  switched  into  the  circuit  by  the  timer.  It  consists  of  a  flat 
steel  spring  secured  at  one  end,  with  the  other  free  to  vibrate.  At  a  point 
about  midway  between  its  ends  contact  is  made  with  the  point  of  an  ad- 
justing screw,  from  which  it  springs  away  and  returns  in  vibrating.  The 
points  of  contact  of  blade  and  screw  are  tipped  with  platinum.  One  wire 
of  the  primary  circuit  is  connected  to  the  blade  and  the  other  to  the 
screw,  hence,  the  circuit  is  made  when  the  blade  is  in  contact  with  the 
screw  and  broken  when  it  springs  away. 

A  condenser  is  used  to  absorb  the  self-induced  current  of  the  primary 
winding  and  thus  prevent  it  from  opposing  the  rapid  fall  of  the  primary 
current.  Every  conductor  of  electricity  forms  a  condenser  and  its  capac- 
ity for  absorbing  a  charge  depends  upon  the  extent  of  its  surface.  Hence, 
a  condenser  is  constructed  of  conductive  material  so  arranged  as  to  pre- 
sent the  greatest  surface  for  a  given  amount  of  material.  The  usual 
form  of  condenser  for  induction  coils  is  composed  of  a  number  of  layers 
of  tin  foil,  separated  by  paraffin  paper,  each  alternate  layer  being  con- 
nected at  the  ends. 

Fig.  195  is  a  diagram  of  a  vibrator  coil,  CC  represents  the  core  com- 
posed of  soft  iron  wires.  PP  is  the  primary  winding  and  SS  the  sec- 
ondary. There  is  no  connection  between  these  windings  and  they  are 
carefully  insulated.  Y  is  the  vibrator  or  trembler  and  D  the  centre  about 
which  Y  vibrates.  W  is  a  switch  used  for  opening  and  closing  the  primary 
circuit;  B,  a  battery  of  five  cells.  The  point  of  the  adjusting  screw  A 
rests  against  a  platinum  point  R  soldered  upon  the  vibrator. 

If  the  switch  W  be  closed,  the  electric  current  generated  by  the  battery 
B  will  flow  through  the  primary  winding.  This  will  cause  the  jore  CC 
to  become  magnetized,  and  the  vibrator  Y  will  at  once  be  drawn  towards 
it.  This  will  break  the  connection  at  R.  The  core,  being  made  of  soft 
iron,  immediately  upon  the  interruption  of  the  current,  will  again  lose 
its  magnetism,  and  the  vibrator  will  return  to  its  original  position.  This 
again  closes  the  circuit,  after  which  the  operation  of  opening  and  closing 
it  is  repeated  with  great  rapidity  so  long  as  the  switch  W  remains 


284 


SELF-PROPELLED    VEHICLES. 


The  cycle  of  actions  may  be  briefly  stated  as  follows : 

1.  A  primary  current  flows  and  magnetizes  the  core. 

2.  The  magnetized  core  attracts  the  vibrator  which  breaks  the 
primary  circuit. 

3.  The  core  loses  its  magnetism  and  the  vibrator  springs  back 
to  its  original  position. 

4.  The   vibrator,  by  returning  to  its   original   position  closes 
the  primary  circuit  and  the  cycle  begins  again. 


FIG.  196.— Circuit  Diagram  of  the  Eiaemann  High-tension  Magneto.  A,  armature ; 
C,  primary  circuit  breaker ;  d,  C2,  C3,  C4,  high-tension  leads  to  cylinders;  D, 
high-tension  distributor  disc;  Di,  D2,  D3,  D4,  distributor  wipe  contacts;  G, 
primary  ground  on  metal  of  engine;  K,  condenser;  M,  permanent  magnets:  N, 
gear  on  distributor  shaft ;  P,  P,  primary  circuit  of  induction  coil;  P,?  P2,  wipe 
contact  on  distributor  rings  of  primary  circuit ;  S,  S,  secondary  circuit ;  T,  bell 
crank  for  timing;  Tt,  spool  in  which  bell  crank  works;  T2,  slotted  sleeve  on 
driven  shaft ;  W,  gear  on  driven  shaft. 

Many  types  of  vibrators  are  used  on  induction  coils,  the  most 
important  requirement  being  that  the  break  occur  with  great 
rapidity.  In  order  to  render  the  break  as  sudden  as  possible, 
different  expedients  have  been  resorted  to,  all  tending  to  make 
the  mechanism  more  complicated,  yet  having  sufficient  merit  in 
most  cases  to  warrant  their  adoption. 

In  the  plain  vibrator,  the  circuit  is  broken  at  the  instant  the 
spring  begins  to  move,  hence  the  operation  must  be  compara- 
tively slow.  In  order  to  render  the  break  more  abrupt  some 
vibrators  have  two  moving  parts,  one  of  which  is  attracted  by 
the  magnetic  core  of  the  coil  and  moved  a  certain  distance  before 
the  break  is  effected.  A  vibrator  of  this  type  is  shown  in  fig.  197 
and  described  under  the  illustration. 


IGNITION. 


285 


When  a  vibrator  coil  is  used,  the  success  or  failure  of  the  igni- 
tion system  depends  largely  upon  the  proper  adjustment  of  the 
vibrator.  The  following  general  instructions  for  adjusting  a 
plain  vibrator  should  be  carefully  noted : 

1.  Remove  entirely  the  contact  adjusting  screw. 

2.  See  that  the  surfaces  of  the  contact  points  are  flat,  clean  and 
bright. 

3.  Adjust  the  vibrator  spring  so  that  the  hammer  or  piece  of 
iron  on  the  end  of  the  vibrator  spring  stands  normally  about 
one-sixteenth  of  an  inch  from  the  end  of  the  coil. 

4.  Adjust  the  contact  screw  until  it  just  touches  the  platinum 
contact  on  the  vibrator  spring — be  sure  that  it  touches,  but  very 
lightly.     Now  start  the  engine ;  if  it  misses  at  all,  tighten  up,  or 


FIG.  197. — A  hammer  vibrator.  When  at  rest,  the  upward  tension  of  the 
spring,  which  carries  the  Armature  A,  holds  the  platinum  points  in 
contact  and  causes  the  upper  spring,  C,  to  leave  shoulder  of  Adjust- 
ing screw,  D,  and  rest  against  the  heavy  brass  plate  above  it.  When 
the  iron  core.  B,  attracts  the  Armature,  A.  the  downward  tension  on 
the  upper  spring.  C,  causes  the  latter  to  follow  the  Armature  down, 
holding  the  platinum  points  in  contact,  until  the  end  of  the  upper 
spring,  C,  strikes  the  lower  shoulder  of  the  adjusting  screw,  D, 
which  gives  it  a  "hammer  break."  The  adjusting  screw  is  held 
firmly  in  position  by  a  bronze  spiral  spring  under  shoulder  D. 

screw  in  the  contact  screw  a  trifle  further — just  a  trifle  at  a  time, 
until  the  engine  will  run  without  missing  explosions. 

In  adjusting  the  vibrator  the  coil  ought  not  to  use  over  one-half  ampere 
of  current. 

Most  spark  coils  have  terminals  marked  "battery,"  "ground,"  etc.,  and 
to  short  circuit  the  timer  for  the  purpose  of  testing  the  vibrator  it  is  only 
necessary  to  bridge  with  a  screw  driver  from  the  "battery"  binding  post  to 
the  "ground"  binding  post. 

A  half  turn  of  the  adjusting  screw  on  a  coil  will  often  increase  the 
strength  of  the  current  four  or  five  times  the  original  amount,  hence  the 


286 


SELF-PROPELLED    VEHICLES. 


necessity  of  carefully  adjusting  the  vibrator.  When  the  adjustment  is  not 
properly  made  it  causes,  i,  short  life  of  the  battery,  2,  burned  contact 
points,  and  3,  poor  running  of  the  engine. 

In  adjusting  a  multi-unit  coil,  if  any  misfiring  be  noticed,  hold  down 
one  vibrator  after  another  until  the  faulty  one  is  located,  then  screw  in  its 
contact  screw  very  slightly. 

The  number  of  cells  in  the  circuit  should  be  proportioned  to  the  design 
of  the  coil.  If  the  coil  be  described  by  the  maker  as  a  4  volt 
coil,  it  should  be  worked  by  two  cells  of  a  storage  battery  or  four  dry 
cells.  The  voltage  of  the  latter  will  be  somewhat  higher,  but  since  their 
internal  resistance  is  also  greater,  the  current  delivery  will  be  about  the 
same.  Most  coils  are  made  to  operate  on  from  4  to  6  volts.  It  is  a  mistake 
to  use  a  higher  voltage  than  that  for  which  the  coil  is  designed,  because 
it  does  not  improve  the  spark  and  the  contact  points  of  the  vibrator  will 
be  burned  more  rapidly,  moreover  the  life  of  the  battery  will  be 
shortened. 


FIG.  198. — Wiring  diagrams  showing  connections  of  some  standard  spark 
coils.  Key:  B — to  Battery;  C — to  Commutator  or  Timer;  G — to 
Ground  (Engine  Frame);  P — to  Plug;  S — to  Switch.  1 — 6  Terminal 
Standard  Non-Vibrator  Coil;  2 — 3  Terminal  Standard  Vibrator  Coil; 
3  and  4 — 4  Terminal  Standard  Vibrator  Coils;  5 — Standard  Double 
Vibrator  Coil;  6 — Standard  Triple  Vibrator  Coil;  7 — Standard 
Quadruple  Vibrator  Coil:  8 — Single  Dash  Coil;  9 — Single  Dash  Coil 
with  Switch:  10 — Double  Dash  Coil:  11 — Double  Dash  Coil  with 
Switch;  12 — Triple  Dash  Coil;  13 — Triple  Dash  Coil  with  switch; 
14 — Quadruple  Dash  Coil;  15 — Sextuple  Dash  Coil. 

Timers. — In  order  that  the  spark  may  occur  at  the  proper  in- 
stant with  respect  to  the  crank  position,  there  must  be  included 
in  all  high  tension  systems,  a  device  called  a  timer  for  closing 


IGNITION. 


287 


and  opening  the  primary  circuit.     This  causes  an  induced  high 
tension  current  to  flow  at  the  instant  the  spark  is  required. 

A  timer  is  simply  a  revolving  switch  operated  by  the  engine. 
It  is  geared  to  revolve  at  one-half  the  engine  speed  in  the  case 
of  a  four  cycle  engine  and  at  full  engine  speed  for  a  two  cycle 
engine. 

All  timers  consist  of  a  stationary  part  and  a  revolving  part  or  rotor.  The 
fornier  is  usually  made  of  a  ring  of  hard  rubber,  into  the  inner  face  of 
which,  is  let  contact  segments  forming  insulated  contacts;  one  of  these 


FIG  199. — Sectional  view  of  the  Pittsfleld  timer.  Contact  is  made  by  means 
of  phosphor  bronze  springs  which  revolve  on  the  timer  shaft  and 
engage  with  stationary  contacts,  set  in  the  timer  ring  and  insulated 
by  hard  rubber.  A  set  screw  fitted  to  the  lower  end  of  the  revolving 
part  allows  it  to  be  placed  on  the  time  shaft  of  any  engine. 

is  provided  for  each  cylinder  of  the  engine.  The  rotor  has  an  arm  which 
makes  contact  with  all  the  insulated  segments  during  one  revolution.  A 
vertical  shaft  geared  to  the  engine  imparts  motion,  by  direct  connection 
to  the  rotor  and  forms,  with  the  rotor  arm.  the  ground  connection  of  the 
primary  circuit.  The  other  wire  of  the  primary  circuit  for  each  cylinder 
is  connected  to  each  stationary  contact. 

Hence,  during  one  revolution  of  the  timer  arm  the  primary  circuit  is 
made  and  broken  once  for  each  cylinder  in  the  proper  sequence. 


288  SELF-PROPELLED     VEHICLES. 

In  order  that  the  spark  may  be  advanced  or  retarded,  that  is,  made  to 
occur  earlier  or  later,  the  timer  must  be  so  arranged  that  the  stationary 
contacts  may  engage  at  a  different  time  with  respect  to  the  engine  cycle. 
This  is  accomplished  by  constructing  the  stationary  part  of  the  timer  so 
that  it  may  rotate  around  the  shaft  through  a  small  arc.  This  movement 
is  controlled  by  a  lever  on  the  steering  column. 

There  are  several  kinds  of  contacts  used  in  timers,  such  as,  brush,  roller, 
and  sliding  contacts. 

A  brush  contact  consists  of  a  brass  brush  which  bears  upon  a  com- 
mutator containing  a  metal  segment  with  which  it  makes  contact  as  the 
commutator  revolves. 

A  roller  contact  consists  of  a  roller,  attached  to  the  end  of  an  arm 
which  is  pivoted  to  the  revolving  part  of  the  timer;  at  the  other  end  of 
the  arm  is  a  spring  whose  tension  causes  the  roller  in  revolving  to  bear 
firmly  against  the  stationary  segments. 

A  sliding  contact  consists  of  a  spring  actuated  device  on  the  revolving 
arm  which  rubs  against  the  stationary  contacts.  An  example  of  this  type 
is  shown  in  section  in  fig  199.  The  revolving  contact  consists  of  two 
phosphor  bronze  springs,  which  make  contact  by  sliding  between  the  two 
projecting  arms  of  the  stationary  terminal  as  shown  in  the  illustration. 


FIG.  200. — A  contact  maker  and  mechanical  vibrator.  The  case.  A,  Is 
usually  attached  to  the  gear  box  of  the  engine;  B  is  the  vibrator 
Made;  C,  a  platinum  contact  point;  D,  an  insulated  adjusting  screw; 
-B,  a  bushing  with  insulation;  F,  the  operating  cam.  As  this  cam 
revolves  the  weight  on  the  end  of  blade,  B,  drops  into  the  recess 
on  the  cam  causing  the  blade  to  vibrate  and  make  a  number  of  con- 
tacts with  D,  thus  producing  a  series  of  sparks  when  in  operation. 

Among  the  special  forms  of  timers,  is  one  with  two  sets  of  contact 
Segments  and  contact  brushes,  forming  practically  a  double  timer  on  a 
single  shaft  and  in  a  single  casing.  The  object  of  this  design  is  to  use 
one  set  of  segments  for  all  ordinary  engine  speeds  and  the  other  for  high 
speeds,  and  thus  to  obviate  waste  of  current  at  low  speeds.  It  is  well 
known  that  in  order  for  the  coil  vibrator  to  operate  properly  at  the  highest 
speed  of  the  motor  the  timer  segments  must  be  made  to  subtend  a  con- 
siderable arc,  usually  forty-five  degrees  in  a  timer  for  a  four  cylinder 
engine.  This  is  a  larger  arc  of  contact  than  is  required  for  normal  speed. 
Suppose,  for  instance,  that  it  suffices  for  a  speed  of  2,100  revolutions  per 
minute,  then  the  length  of  contact  at  700  revolutions,  which  would  prob- 


IGNITION. 


289 


ably  correspond  nearly  to  the  average  speed  of  the  motor,  would  be  three 
times  as  long  as  necessary,  and  ther<>  would  be  a  corresponding  waste  of 
current.  Hence,  a  variable  contact  arc  is  necessary  for  economy  of  cur- 
rent. 

As  constructed,  one  set  of  segments  give  a  contact  of  15°  and  the  other 
set  45.°  Either  set  may  be  brought  into  use  by  a  switch  having  two  posi- 
tions marked  "touring"  and  "speed,"  the  short  segments  being  used  for 
slow  speed  and  the  long  segments  for  high  speed. 

In  addition  to  the  three  methods  of  closing-  and  opening  the 
primary  circuit,  as  just  described,  this  operation  is  also  accom- 
plished by  simply  touching  the  contact  points.  There  are  two 
classes  of  timing  devices  which  work  on  this  principle,  viz : 

1.  Contat  '•  makers. 

2.  Contact  breakers. 


FIG.  201. — A  contact  breaker.  This  device  keeps  the  circuit  closed  at  all 
times  except  during  the  brief  interval  necessary  for  the  passage  of 
the  spark  at  the  plug  points.  Used  to  advantage  on  engines  running 
at  very  high  speeds,  as  it  allows  time  for  the  magnetic  flux  in  the 
core  of  the  coil  to  attain  a  density  sufficient  to  produce  a  good  spark. 

Fig.  200  shows  one  form  of  contact  maker  which  serves  also 
to  illustrate  what  is  known  as  a  mechanical  vibrator. 

The  case  A  is  usually  connected  to  the  gear  box  of  the  engine.  A 
flat  steel  spring  B  is  attached  to  A.  An  insulated  screw  D  is  so  ad- 
justed that  it  does  not  touch  the  platinum  point  C  of  the  blade  B  unless 
acted  upon  by  the  cam.  As  the  cam  F  revolves  in  the  direction  indicated  by 
the  arrow,  it  comes  into  contact  with  a  metal  nose  attached  to  the  end 
of  the  blade  B. 

Shortly  before  the  cam  has  arrived  at  the  position  shown  in  the  figure, 
the  pressure  due  to  the  action  of  the  spring  causes  the  nose  to  suddenly 
drop  into  the  depression  in  the  cam.  Its  momentum  carries  it  past  its 
normal  position  and  the  point  C  makes  contact  with  the  insulated  screw. 
The  metal  nose,  on  account  of  its  weight,  will  cause  the  blade  B  to  vibrate, 


290  SELF-PROPELLED    VEHICLES. 

bringing  the  contact  points  together  several  times  before  the  cam  again 
engages  the  nose.  This  form  of  contact  maker,  is  called  a  mechanical 
vibrator. 

In  the  plain  form  of  contact  maker  the  circuit  is  closed  and  opened 
once  only  for  each  revolution  of  the  cam,  which  in  this  case  has  a  projec- 
tion or  nose  on  its  circumference  instead  of  a  sharp  depression.  This 
engages  the  contact  blade  and  presses  it  against  the  insulated  screw  to 
close  the  circuit. 

Since  the  operation  of  a  contact  maker  keeps  the  circuit  closed  for  only 
a  short  interval,  it  has  been  found  necessary,  with  some  forms  of  high 
speed  engines,  to  keep  the  battery  and  coil  in  a  closed  circuit,  except 
during  the  brief  interval  necessary  for  the  passage  of  the  spark.  This 
allows  the  needed  time  for  the  magnetic  flux  of  the  core  of  the  magnet  to 
attain  a  sufficient  density  to  induce  a  secondary  current  of  the  required 
strength.  A  device  known  as  a  contact  breaker  is  used  for  this  closed 
circuit  working. 

One  form  of  contact  breaker  is  shown  in  fig.  201.  At  the  left  of  the 
figure  is  an  insulated  screw.  One  end  of  a  pivoted  lever  is  kept  in  contact 
with  the  screw  by  a  spring  as  shown,  except  at  the  time  of  the  spark.  A 
roller  is  attached  to  the  other  end  of  the  lever,  directly  below  which  is  a 
ciin.  When  the  nose  of  the  cam  engages  with  the  roller,  the  contact 
points  quickly  separate,  thus  breaking  the  circuit  and  producing  a  spark. 

Distributers. — When  one  secondary  coil  only  is  used  with  a 
multi-cylinder  engine  as  in  synchronous  ignition,  a  device  called  a 
distributer  is  a  necessary  part  of  the  system.  Its  use  is  to  direct 
the  discharge  of  a  single  coil  to  the  spark  plug  of  each  cylinder 
in  rotation.  A  distributer  consists  of  a  timer  for  the  primary 
current  and  a  similar  device  working  synchronously,  that  is,  in 
step  with  the  timer  and  which  switches  the  secondary  current  to 
the  various  spark  plugs  in  the  proper  order  of  firing. 

In  other  words,  a  distributer  is  a  combination  of  two  timing  devices 
working  in  unison  with  each  other;  one  makes  and  breaks  the  primary 
circuit,  while  the  other  makes  and  breaks  the  secondary  circuit  and  in 
so  doing  distributes  the  current  to  the  several  cylinders  in  correct 
sequence. 

The  spark  is  advanced  or  retarded  by  the  same  method  employed  with 
a  timer  as  previously  explained. 

The  primary  element  of  a  distributer  contains  as  many  stationary 
contacts  as  there  are  cylinders  and  a  revolving  arm  or  rotor  which  in  its 
revolution  touches  each  of  the  stationary  contacts  so  that  the  primary 
circuit  is  made  and  broken  once  for  each  cylinder  during  one  revolution 
of  the  arm. 

The  secondary  element  is  above  and  concentric  with  the  primary  part 
It  has  a  rotor  and  the  same  number  of  stationary  contacts^  as  the  primary 
element ;  the  parts  of  both  elements  are  arranged  synmetrically  with  each 
other  and  are  contained  in  a  compact  cylindrical  casing.  A  shaft  geared 
to  the  engine  operates  both  the  primary  and  secondary  rotors. 

The  primary  rotor  is  in  metallic  contact  with  the  shaft  and  forms  with 
»t  and  the  engine  a  ground  return  for  the  primary  circuit. 


IGNITION. 


291 


The  secondary  rotor  is  carefully  insulated.  All  the  primary  stationary 
contacts  are  connected  to  one  common  terminal  which  receives  the  primary 
lead.  A  binding  post  is  provided  for  each  of  the  secondary  stationary 
contacts  and  one  for  the  secondary  rotor.  These  binding  posts  are  usually 
placed  on  the  top  part  of  the  casing. 

Fig.  202  is  a  sectional  view  of  a  modern  distributer,  which  differs  in 
some  respects  from  the  foregoing  description.  The  primary  element 


10 


FIG.  202. — Sectional  view  of  the  Pittsfield  distributer.  In  this  device 
several  revolving  contacts  are  employed  instead  of  one;  these  con- 
sist of  a  double  spring  making  sliding  contact  at  the  portions,  A. 
The  parts  are:  1,  contact  springs;  2,  shaft;  3,  bushing;  4,  stationary 
terminal;  5,  timer  ring;  6,  stationary  contact  insulation;  7,  distrib- 
uter plate:  8,  secondary  revolving  contact  segment;  9,  taper  pin; 
10,  secondary  stationary  terminals;  11.  casing;  12,  secondary  ter- 
minal for  lead  to  coil;  B,  slide  bearings;  C,  hook;  D,  eye;  E, 
secondary  cable.  The  operation  of  this  distributer  is  described  in  the 
text. 


292  SHIP-PROPELLED    VEHICLES. 

consists  of  two  springs,  i,  fastened  to  the  shaft  2.  The  latter  is  fitted  at 
its  lower  end  with  a  bushing  3  containing  two  set  screws  to  secure  it  to  the 
timer  shaft  of  the  engine.  It  should  be  noted  that  instead  of  having  a 
stationary  contact  4,  for  each  cylinder,  only  one  is  provided,  but  there 
are  additional  revolving  contacts  A  so  that  the  current  is  made  and 
broken  once  for  each  cylinder  during  one  revolution  of  the  rotor.  To  the 
shaft  2,  is  fitted  a  hard  rubber  distributer  plate  7,  with  segment  8,  .by 
taper  pin  9.  As  soon  as  the  springs  i  make  contact  with  the  terminal  4, 
segment  8  comes  in  contact  with  one  of  the  terminals  10,  inserted  in  the 
casing  n.  The  wiring  and  operation  of  the  distributer  system  is  later 
explained  under  "synchronous  ignition." 

In  some  types  of  distributers  an  auxiliary  spark  gap  is  included  in  the 
design.  The  secondary  rotor  is  arranged  so  that  it  does  not  actually 
touch  the  stationary  segments  but  terminates  very  closely  to  them,  the  cur- 
rent being  required  to  jump  through  the  short  gap  intervening  between  the 
arm  and  segments.  This  space  acts  as  an  auxiliary  spark  gap. 

Spark  Plugs. — In  all  high  tension  ignition  systems  a  perman- 
ent air  gap  is  placed  in  the  secondary  circuit  across  which  the 
current  must  jump  to  produce  a  spark.  The  device  by  which 
this  permanent  air  gap  is  maintained  is  called  a  spark  plug. 
There  are  several  varieties  of  these  as  follows : 

Primary  or  magnetic  make  and  break  plugs. 
Secondary  plugs. 

Duplex  plugs. 

Coil  plugs. 

The  primary  plug  has  already  been  described  in  that  section 
of  this  chapter  devoted  to  low  tension  ignition  devices ;  the  others 
will  now  be  explained. 

Secondary  Spark  Plugs. — This  type  of  plug  used  for  a 
secondary  or  high  tension  spark  plug  is  made  up  of  three  elements 
as  follows: 

1.  A  ground  electrode. 

2.  An  insulated  electrode. 

3.  Insulating  material  separating  the  two. 

The  construction  of  a  few  typical  spark  plugs  is  shown  in 
fig.  203. 


IGNITION. 
In  general,  the  construction  is  as  follows : 


293 


FIG.    203. — Sections    of    well    known    spark    plugs, 
porcelain  insulation;    the  last  two,  mica. 


The   first   five   have 


I.  The  ground  electr-ode  is  attached  to  a  metal  cup  which  has  an 
external  thread  so  that  it  may  be  screwed  into  the  metal  of  the  cylinder, 
thus  forming  the  ground  connection  of  the  secondary  circuit. 


294  SELF-PROPELLED     VEHICLES. 

2.  The  insulated  electrode  consists  of  a  thin  metal   rod  located  in  the 
center  of  the  plug,  and  whose  end  is  separated  from  the  ground  electrode 
by  about  one  thirty-second  of  an  inch.     The  space  between  the  terminals 
of  the  two  electrodes  is  called  the  air  gap. 

3.  The    insulating    material,    forming    the    third    element    mentioned,    is 
usually    of   porcelain   or    mica    and   cylindrical    in    shape.      It    is    retained 
firmly    within    the   metal    cup    which    separates    the    two    electrodes   by    a 
threaded  bushing. 

Failure  of  the  insulation  may  occur  from  several  causes.  It 
sometimes  happens  that: 

i.  The  material  becomes  covered  with  a  coating  of  soot  which, 
possessing  considerable  conductivity,  affords  an  easier  path  for 
the  current  than  the  air  gap. 

2..  The  material  becomes  saturated  with  conducting  matter, 
thus  reducing  its  efficiency  and  causing  a  liability  of  short  cir- 
cuits. 

Porcelain  is  well  suited  for  insulating  material,  since  it  possesses  a  very 
high  resistance  both  to  heat  and  to  the  electric  current.  In  fact,  a  high 
quality  of  porcelain  should  not  break  down  with  either  the  heat  or  the 
electrical  tension  encountered  in  gas  engine  operation.  That  porcelains 
are  broken  under  such  conditions  is  due  to  uneven  heating  of  the  insulat- 
ing tube  or  to  some  unexpected  violence.  The  brittleness  of  porcelain 
is  the  most  serious  objection  to  its  use.  Lower  qualities  of  porcelain  are, 
of  course,  much  more  easily  broken,  and  thereby  produce  short  circuiting 
under  ordinary  conditions  of  temperature  and  electrical  tension.  Many 
plugs  using  porcelain  insulation  have  the  porcelain  in  two  or  more  parts, 
so  as  to  avoid  the  troubles  arising  from  uneven  temperatures.  Heat  is 
liable  to  break  a  single  long  porcelain. 

Mica  is  an  ideal  insulator,  except  for  the  fact  that  it  frequently  con- 
tains impurities  which  reduce  its  insulating  efficiency,  and  also  because, 
owing  to  its  laminated  structure,  oil  and  gas  may  be  forced  by  the  pres- 
sure of  compression  between  the  sheets  composing  the  insulating  sheath, 
thus,  in  time,  producing  short  circuiting  of  the  current.  Most  mica 
insulated  plugs  having  the  inner  spindle  sheathed  with  concentric  coats 
of  mica  have  also  a  cap  at  the  end  of  the  sheath  to  protect  it  and  to  insure 
the  attachment  of  the  spindle. 

In  many  modern  spark  plugs  there  is  an  annular  clearance  between  the 
insulating  material  and  the  inside  of  the  metal  cups.  In  some  plugs  an 
additional  annular  clearance  is.  provided  between  the  insulating  material 
and  the  insulated  electrode.  This  is  provided  for  the  purpose  of  reducing 
the  danger  by  short  circuit  by  leaving  a  larger  space  between  the  two 
electrodes  than  will  ordinarily  be  filled  with  soot.  According  to  some 
designers,  it  also  insures  a  vortex  for  the  gases,  circulating  in  the  com- 
bustion chamber,  under  the  impulse  of  the  piston  strokes,  thus  expelling 
a  large  part  of  the  deposits. 

Duplex  Spark  Plug. — These  are  designed  to  work  on  a  me- 
tallic circuit,  that  is,  one  in  which  the  secondary  current  is  car- 


IGNITION.  295 

ried  by  a  visible  lead  and  not  grounded  at  any  point.  This  type 
consists  of  a  double  plug  constructed  so  that  both  electrodes  are 
insulated  as  illustrated  in  fig.  204. 

Coil  Spark  Plugs. — A  plug  of  this  class  consists  of  an  ordi- 
nary plug  combined  with  a  plain  secondary  induction  coil.  The 
latter  is  superposed  on  the  plug  and  contained  in  a  cylindrical 
casing,  the  vibrator  and  condenser  being  located  in  a  separate 
box ;  the  object  in  this  case  being  to  minimize  the  secondary 
leakage,  to  have  all  parts  easily  accessible,  and  to  simplify  the  wir- 
ing. 


FIG.  204. — A  duplex  or  double  spark  plug.  Unlike  other  plugs,  the 
secondary  circuit  is  carried  by  visible  leads,  and  is  not  grounded  at 
any  point. 

Sparking  Pressure. — A  current  of  very  high  voltage  is  re- 
quired to  produce  a  secondary  or  jump  spark  on  account  of  the 
great  resistance  of  the  air  gap  and  compression  pressure  which 
oppose  the  current  flow. 

The  required  voltage  will  depend  on  the  length  of  the  air  gap  and  the 
intensity  of  the  pressure  inside  the  cylinder.  For  ordinary  spark  plugs 
in  air  the  sparking  pressure  will  vary  from  about  3,000  to  5,000  volts 
according  to  the  length  of  the  gap,  but  to  produce  a  spark  in  an  engine 
cylinder  where  the  mixture  has  been  compressed  to  four  or  five  times  the 
atmospheric  pressure,  will  require  from  10,000  to  20,000  volts. 

When  a  spark  plug  will  not  work,  the  electrodes  and  insulating  mater- 
ial should  be  thoroughly  cleaned  with  fine  sandpaper  and  the  distance 
between  the  points  adjusted  to  about  one  thirty-second  of  an  inch,  or  the 
thickness  of  a  ten  cent  silver  piece.  To  increase  the  gap  between  the 
points,  a  knife  blade  can  be  used  to  advantage.  If  the  battery  be  weak, 
the  gap  may  be  made  smaller — about  one  sixty-fourth  of  an  inch. 

Spark  plugs  are  often  damaged  by  placing  a  wrench  upon  the  top  or 
lock  nut.  The  plug  should  be  screwed  in  just  tight  enough  to  prevent 
leakage,  An  extra  spark  plug  should  be  carried  as  an  accessory. 


296  SELF-PROPELLED     VEHICLES. 

Safety  Air  Gap. — It  is  usual  to  fit  high  tension  magnetos  with 
a  device  called  a  safety  air  gap.  Should  the  resistance  of  the 
spark  plug  become  too  great  to  permit  a  spark  to  jump,  the  vol- 
tage of  the  secondary  current  might  rise  to  an  intensity  suffi- 
cient to  destroy  the  coil.  To  avoid  this,  an  air  gap  is  introduced 
in  the  secondary  circuit  connected  in  parallel.  This  allows  the 
pressure  to  rise  only  to  a  certain  maximum  after  which  a  dis- 
charge will  take  place  through  the  safety  gap. 

Auxiliary  Air  Gap. — This  consists  of  two  adjustable  elec- 
trodes, having  their  terminals  slightly  separated  and  placed  in 
the  secondary  circuit  in  series  with  the  plug.  Its 
object  is  to  prevent  any  leakage  of  current  in 
case  of  defective  plug  insulation  by  preventing 
the  flow  of  the  secondary  current  until  the  voltage 
has  been  raised  enough  to  suddenly  break 
down  the  resistance  of  the  auxiliary  gap  and  also 
that  of  the  plug.  This  results  in  a  discharge 
through  the  air  gap  of  plug  instead  of  over 
the  sooted  surfaces  of  the  plug  insulation. 

As    usually    constructed,    the    auxiliary    air   gap 
^auxiliary  air    consists  of  two  adjustable    electrodes,    set    into    a 
gap<  short  piece  of  glass  tubing  as  shown  in  fig.  205. 

High  Tension  Ignition  Circuits. — In  any  jump  spark  system, 
two  distinct  circuits  are  necessary : 

1.  A  primary  or  low  tension  circuit. 

2.  A  secondary  or  high  tension  circuit. 

The  primary  circuit  is  composed  of,  i,  a  source  of  current  sup* 
ply,  2,  a  timer,  3,  a  switch  and  4,  the  primary  winding  of  an  in- 
duction coil.  These  elements  are  joined  in  series,  the  circuit  be~ 
ing  completed  by  a  ground  return. 

The  secondary  circuit  includes  I,  the  spark  plug  and  2,  the  secondary 
winding  of  the  coil.  One  end  of  the  secondary  winding  is  connected  to  the 
insulated  electrode  of  the  spark  plug;  the  other  end  is  grounded  to  the 
metal  of  the  engine ;  as  illustrated  in  fig.  207  to  be  described  in  detail  later. 


IGNITION. 


297 


In  high   tension   ignition,   there   are   several   systems   among 
which  may  be  mentioned  those  using: 

1.  Plain  coils  with  contact  makers  or  contact  breakers. 

2.  Plain  coils  with  mechanical  vibrators. 

3.  Vibrator  coils. 

4.  Plain  coils  with  master  vibrators. 

5.  Single  coils  with  distributers:  synchronous  ignition. 


FIG.  206. — Remy  wiring  diagrams  for  two  and  four  cylinder  motors.  This 
dual  ignition  system  consists  of  a  Remy  high  tension  magneto, 
battery,  coil,  and  one  set  of  spark  plugs.  The  special  coil  furnished 
with  the  magneto  is  fitted  with  a  two  point  switch,  used  to  switch 
from  battery  to  magneto  or  vice  versa,  or  disconnect  from  either  to 
stop  the  motor.  The  push  button  is  for  starting  from  the  spark  with 
switch  turned  to  the  battery  side.  When  the  battery  is  used,  the 
current  is  simply  turned  through  the  coil  and  distributer  of  the 
magneto  instead  of  the  magneto  current.  The  speed  of  the 
magneto  is  the  same  as  that  of  the  crank  shaft  for  a  two  cylinder 
motor,  and  twice  the  crank  shaft  speed  for  four  cylinders. 

6.  High  tension  magnetos. 
J.  Coil  spark  plugs. 
8.  Special  igniting  devices. 

These  several  systems  will  now  be  taken  up  in  the  order  given 
with  a  brief  explanation  of  each. 


298 


SELF-PROPELLED    VEHICLES. 


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IGNITION.  299 

Ignition  with  Plain  Coils. — The  first  high  tension  system  to 
attain  popularity  was  the  single  spark  system  using  a  plain  coil 
and  contact  maker.  This  being  the  simplest  method  of  produc- 
ing a  secondary  spark,  it  will  serve  to  illustrate  the  several  prin- 
ciples involved  in  jump  spark  or  high  tension  ignition. 

Fig.  207  is  a  wiring  diagram  showing  the  connections.  In  the  figure 
the  primary  and  secondary  windings  of  a  plain  coil  are  shown  separated 
instead  of  overlapping,  so  that  the  circuits  may  be  easily  traced.  As 
before  stated,  two  distinct  circuits  are  necessary  to  produce  a  jump  spark, 
i,  the  primary,  and,  2,  the  secondary. 

The  operation  is  as  follows :  the  primary  switch  is  first  closed  and  then 
the  engine  cranked.  As  the  piston  approaches  the  upper  dead  centre  on 
the  compression  stroke,  the  nose  of  the  contact  maker  cam  engages  the 
blade  and  brings  the  contact  points  together,  thus  completing  the  primary 
circuit.  Current  now  flows  from  the  plus  terminal  of  the  battery,  through 
the  switch,  thence  to  the  metal  of  the  engine  and  to  the  blade  of  the 
contact  maker.  From  this  point  it  flows  through  the  insulated  screw, 
lead  and  primary  winding  of  the  coil,  and  thence  through  the  return  wire 
to  the  negative  terminal  of  the  battery,  thus  completing  the  circuit.  This 
is  indicated  by  the  arrows. 

The  action  of  the  cam  allows  the  contact  points  to  touch  each  other 
for  only  a  very  short  time.  It  should  be  remembered  that  the  primary 
and  secondary  wires  do  not  come  in  contact  with  each  other,  both  having 
an  insulating  covering. 

The  momentary  current  flowing  in  the  primary  winding,  induces  a 
current  of  high  pressure  in  the  secondary  winding,  but  which  flows  in  a 
direction  opposite  to  that  of  the  primary  current  as  shown  by  the  arrows. 
This  induced  current  flows  from  one  end  of  the  secondary  winding,  to 
the  metal  of  the  engine  and  the  ground  electrode  of  the  spark  plug.  It 
then  produces  a  spark  by  jumping  the  air  gap,  thence  it  returns  from  the 
insulated  electrode  of  the  plug  to  the  secondary  winding  of  the  coil,  com- 
pleting the  circuit. 

Instead  of  a  contact  maker,  this  system  may  be  operated  by  a  contact 
breaker.  With  this  device,  the  primary  circuit  remains  closed  except  at 
the  time  of  the  spark.  It  is  evident  that  the  primary  current  will  flow  for 
?.  much  longer  interval  with  a  contact  breaker  than  with  a  current  maker. 
This  closed  circuit  working  of  the  contact  breaker  is  necessary  with  some 
forms  of  engines  running  at  unusually  high  speeds  in  order  to  allow  suf- 
ficient time,  as  before  explained,  for  the  magnetic  flux  in  the  core  of  the 
coil  to  attain  a  density  sufficient  to  produce  a  good  spark  at  the  plug 
points. 

Ignition  with  Mechanical  Vibrators. — The  view  held  by 
some  that  a  series  of  sparks  closely  following  each  other  is  more 
effective  for  ignition  than  a  single  spark,  led  first  to  the  introduc- 
tion of  the  mechanical  vibrator.  This  system  employs  a  plain 


300 


SELF-PROPELLED    VEHICLES. 


coil  and  is  identical  with  the  one  just  described  with  the  exception 
that  in  place  of  the  make  or  break  timing  device,  a  mechanical 
vibrator  is  used  which  gives  a  succession  of  sparks  for  firing 
each  charge. 

Ignition  with  Vibrator  Coils. — A  more  refined  method  of 
producing  a  series  of  sparks  for  igniting  the  charge  is  by  the 
use  of  vibrator  coils.  The  magnetic  vibrator  is  a  marked  improve- 
ment on  the  mechanically  operated  device  as  it  vibrates  with 


FIG  208— Wiring  diagram  of  a  dual  jump  spark  system  for  a  four- 
cvlinder  four  cycle  engine.  A  dry  battery  and  low  tension  magneto 
form  the  two  source!  of  current  supply.  The  primary,  or  low 
tension  circuit  is  shown  by  heavy  lines,  the  secondary  or  hig 
Union  circuit  by  fine  lines  and  the  leads  to  spark  plugs  by  the 
double  lines.  The  dotted  rectangle  represents  the  outline  of  a  four 
unit  dash  coil. 

greater  rapidity  and  is  capable  of  delicate  adjustment.  This  sys- 
tem which  is  extensively  used  is  illustrated  in  fig.  208,  which  is  a 
wiring  diagram  for  a  four  cylinder  engine.  The  dotted  rectan- 
gle represents  the  casing  of  a  quadruple  or  four  unit  secondary 


IGNITION.  301 

coil.  The  heavy  lines  show  the  primary  circuit,  the  fine  lines,  the 
secondary  windings  of  the  coils,  and  the  double  lines  the  leads  of 
insulated  wire  to  the  spark  plugs. 

In  the  coil  connections  it  should  be  noted  that  the  adjustable  contact 
screw  of  each  vibrator  is  connected  by  a  common  wire  terminating  at  the 
two-way  switch ;  also,  in  each  unit,  one  end  of  the  secondary  winding  is 
connected  to  that  end  of  the  primary,  leading  to  the  vibrator  blade.  These 
common  connections  simplify  the  external  wiring,  as  otherwise  there 
would  be  four  binding  posts  for  each  unit. 

The  two-way  switch  just  referred  to  permits  the  current  supply  to  be 
taken  from  either  of  two  sources,  such  as  a  battery  and  a  magneto. 
Current  is  supplied  by  the  battery  when  the  switch  is  in  the  position  shown 
in  the  figure.  By  turning  the  switch  to  the  right,  a  current  from  the 
magneto  will  be  furnished. 

With  the  battery  in  the  circuit  and  the  timer  in  the  position  shown,  the 
operation  is  as  follows : 

Current  flows  from  the  positive  terminal  of  the  battery,  to  the  switch, 
thence,  to  the  contact  screw  of  coil  number  two.  From  here,  it  flows 
through  the  vibrator  blade,  primary  winding  of  the  coil  timer  and  the 
metal  of  the  engine,  and  returns  to  the  battery.  The  primary  circuit  is 
alternately  opened  and  closed  with  great  rapidity  by  the  vibrator  so  long 
as  the  rotor  of  the  timer  is  in  contact  with  terminal  2.  During  this  in- 
terval, a  series  of  high  tension  currents  are  induced  in  the  secondary 
circuit  producing  a  succession  of  sparks. 

These  currents  flow  through  the  secondary  winding  in  a  direction 
opposite  to  that  of  the  primary  current.  At  each  interruption  of  the 
primary  current,  an  induced  high  tension  current  flows  through  the  sec- 
ondary winding,  to  the  spark  plug,  across  the  gap  producing  a  spark 
and  returns  through  the  metal  of  the  engine,  tinier  and  back  to  the  coil. 

As  the  rotor  of  the  timer  revolves  it  touches  each  of  the  stationary 
contacts  and  in  so  doing  the  above  cycle  is  repeated  for  each  cylinder  in 
the  order  of  firing,  as  wired. 

Ignition  with  a  Master  Vibrator. — In  a  multi-unit  coil  there 
is  a  vibrator  for  each  unit,  all  of  which  may  be  operated  by  a 
single  or  master  vibrator.  The  advantage  of  such  a  system  is 
that  there  is  but  one  vibrator  to  keep  in  adjustment,  since  this 
vibrator  serves  for  all  the  cylinders ;  whereas,  with  one  for  each 
unit,  all  have  to  be  kept  in  adjustment  and  the  difficulty  of  keep- 
ing the  several  adjustments  is  a  considerable  factor. 

In  fig.  209  is  shown  a  master  vibrator  coil.  This  has  but  one  vibrator  V 
for  the  four  units  of  the  coil,  these  being  designated  respectively  C,  C,  C, 
C,  and  each  consisting  of  a  primary  winding  P  and  a  secondary  wind- 
ing S. 

The  primary  windings  are  all  united  in  parallel  at  the  top  by  a  wire 
W,  and  with  the  lower  ends  connecting  respectively  with  the  segments  of 


302 


SELF-PROPELLED    VEHICLES. 


the  tinier  T.  The  primary  winding  MP  which  operates  the  vibrator 
V  is  in  series  with  this  winding,  the  wire  WT  connecting  from  the  battery 
and  passing  directly  through  the  master  primary  MP.  The  four  con- 
densers, Ci,  C2,  C3  and  C4,  are  in  parallel  with  the  primary  windings. 
Each  of  the  secondary  windings  S  connects  direct  to  the  spark  plugs, 
designated  respectively  Hi,  H2,  H3  and  H4. 

Fig.  210  illustrates  the  Splitdorf  master  vibrator,  in  which  the  four  coils 
are  designated  I,  2,  3  and  4,  and  a  fifth  unit  V  in  the  left  end  of  the  box, 
contains  the  master  vibrator.  The  four  primary  windings  connect  direct 
by  the  wires  P  with  the  timer,  and  the  secondaries  are  connected  direct 
with  the  plugs.  The  internal  wirings  of  all  of  the  primaries  are  in 
parallel  with  the  electro  magnet  in  the  unit  V  which  operates  the  master 
vibrator. 


PIG.  209. — Circuit  diagram  of  a  master  vibrator  coil.  B,  is  the  battery; 
C,  the  unit  coils;  Cl,  C2,  etc.,  the  condensers;  P,  the  primary 
winding's  and  S,  the  secondary  windings;  Hi,  H2,  etc.,  the  spark 
plugs;  T,  the  timer;'  MP,  the  master  primary;  V  the  vibrator;  W, 
the  common  primary  connection;  1,  2,  etc.,  the  stationary  contacts 
of  the  timer. 


Synchronous  Ignition. — This  system  employs  a  distributer 
and  a  single  coil  for  a  number  of  cylinders.  It  is  called  "syn- 
chronous" for  the  following  reason:  when  a  multi-cylinder  en' 
gine  has  a  coil  unit  for  each  cylinder,  it  requires  the  adjustment 
of  several  vibrators.  Now,  the  time  required  by  the  vibrator  to 


IGNITION. 


303 


act  is  variable  with  the  adjustment,  and  with  slight  differences  in 
construction,  hence,  of  the  several  vibrators,  perhaps  no  two  will 
act  in  exactly  the  same  time.  Consequently,  though  in  the  ordi- 
nary multiple  coil  system  the  closing  of  the  primary  circuits  may 
occur  at  exactly  corresponding  moments  for  all  of  the  cylinders, 
the  production  of  the  spark  of  ignition  will  be  more  or  less  "out," 
owing  to  the  variation  in  the  "lag"  of  the  different  vibrators. 

With  a  distributer  and  single  coil,  the  lag  is  the  same  for  all 
the  cylinders,  hence,  the  application  of  the  word  synchronous. 

Fig.  211  is  a  wiring  diagram  showing  the  connections  of  a  synchronous 
system;  for  clearness,  the  two  windings  of  the  coil  are  shown  separated 
from  each  other  and  for  the  same  reason  also  the  primary  and  secondary 
elements  of  the  distributer  are  separated. 


FIG.  210. — The  Splitdorf  master  vibrator  coil.  As  shown  In  the  Illustra- 
tion the  several  unit  coils  are  indicated  by  the  figures  1,  2,  3  and  4.  A 
fifth  unit  V  at  the  left  contains  the  master  vibrator.  The  primary 
wires  P  connect  with  the  timer  and  the  secondary  wires  S  with  the 
plugs.  B  B  shows  the  battery  connections. 

The  primary  rotor  of  the  distributer  being  in  contact  with  one  of  the 
stationary  segments,  the  path  of  the  primary  current  is  as  follows :  from 
the  plus  terminal  of  the  battery  to  the  metal  of  the  engine,  through  the 
primary  element  of  the  distributer  and  the  primary  winding  of  the  coil; 
thence  to  the  virbrator  blade,  contact  screw  and  back  to  the  battery  by  the 
return  wire  as  indicated  by  the  arrows.  During  the  time  the  primary 
rotor  is  in  contact  with  the  stationary  segment,  the  primary  circuit  is 


304 


SELF-PROPELLED     VEHICLES. 


opened  and  closed  with  great  frequency  by  the  vibrator.  This  produces 
a  series  of  induced  currents  in  a  reverse  direction  through  the  secondary 
winding  of  the  coil. 

Each  secondary  segment  of  the  distributer  being  wired  to  one  of  the 
spark  plugs,  the  rotor  during  its  revolution  brings  each  plug  into  the 
secondary  circuit  in  the  order  indicated  in  the  diagram.  As  shown,  the 
secondary  rotor  is  in  contact  with  segment  number  two  which  causes  the 
induced  current  to  flow  from  the  secondary  winding,  through  the  dis- 


.  cOa 

I  CONTACT   SCREW 


BATTERY 


FIG.  211. — Diagram  Illustrating  the  principles  of  synchronous  ignition. 
For  clearness  the  primary  and  secondary  elements  of  both  the  coiJ 
and  the  distributer  are  shown  separated.  When  the  primary  rotor 
of  the  distributer  completes  the  primary  circuit,  current  from  the 
battery  flows  and  the  vibrator  operates,  making  and  breaking  the 
current  with  great  frequency.  A  high  tension  current,  made  up  of 
a  series  of  impulses,  is  induced  in  the  secondary  circuit  and  dis- 
tributed by  the  rotor  arm  during  its  revolution  to  the  several 
cylinders  in  the  proper  order  of  firing. 

tributer,  thence  to  the  spark  plug,  across  the  gap,  through  the  metal 
of  the  engine  and  back  to  the  coil  by  the  return  wire  as  indicated  by  the 
arrows. 

One  end  of  the  secondary  winding  is  usually  connected  to  one  end 
of  the  primary  winding  instead  of  making  a  separate  connection  to  the 
metal  of  the  engine.  This  simplifies  the  wiring  by  having  one  common 
ground  connection. 


IGNITION.  305 

In  adopting  a  coil  for  use  with  a  distributer,  the  one  should  be  selected 
which  gives  the  required  spark  with  the  least  primary  current,  and  which 
shows  freedom  from  vibrator  trouble  and  the  minimum  effect  on  the 
points  after  a  continuous  closed  circuit  test  of  at  least  ten  hours.  No  coil 
has  been  produced  which  will  not  in  time  show  some  pitting  of  the  vi- 
brator points,  especially  if  the  direction  of  the  primary  current  be  always 
the  same.  A  coil  worked  from  a  four  point  distributer  will  show  a  given 
amount  of  pitting  in  rather  less  than  a  quarter  of  the  time  required  to 
produce  the  same  effect  if  the  coil  be  one  of  four  coils  operated  from 
a  timer. 

It  is  good  judgment  to  carry  a  spare  coil  unit,  no  matter  which  system 
is  used,  and  it  should  be  kept  in  good  condition  so  that  no  time  need  be 
lost  if  a  change  be  required. 

In  connecting  up  batteries  and  coils  it  is  recommended  that  the  vibrator 
screws  be  made  "positive,"  so  that  whatever  platinum  is  carried  away  by 
the  arc  may  be  taken  from  the  screw  and  deposited  upon  the  contact  point 
of  the  vibrator.  The  theory  is  that  the  screw  is  cheaper  and  easier  to 
replace  than  is  the  vibrator,  and  that,  with  this  arrangement,  the  vibrator 
point  builds  up  rather  than  wears  away,  requiring  only  the  smoothing  off 
of  the  extra  metal  deposited  upon  it  to  keep  it  in  condition. 

The  very  slight  wear  produced  upon  vibrators  operated  from  non- 
synchronous  alternating  current  magnetos  from  which  the  current  is  in 
each  direction  for  one-half  of  the  time,  in  the  aggregate,  is  well  known. 
Hence,  when  a  battery  is  used,  if  the  operator  would  periodically  change 
the  direction  of  the  current  flow  by  reversing  the  two  battery  wires  con- 
necting the  one  which  has  gone  to  the  positive  pole,  to  the  negative  and 
vice  versa,  he  will  find  that  the  wear  of  the  vibrator  points  is  reduced  to 
a  minimum. 

Magneto  Ignition. — There  are  numerous  types  of  magnetos 
used  for  igniting  purposes.  In  the  several  systems,  therefore,  dif- 
ferent methods  of  wiring  are  required.  In  the  true  high  tension 
and  the  self-contained  types  where  the  coil  and  condenser  are  a 
part  of  the  magneto,  the  number  of  external  connections  is  less 
than  with  those  having  the  coil  in  a  separate  box.  One  advant- 
age of  magneto  ignition  is  that  it  does  not  require  hand  advance 
of  the  spark.  The  intensity  of  a  magneto  current  increases  with 
the  speed,  hence,  when  running  slowly  the  spark  produced  in  the 
cylinder  will  be  weak  and  the  charge  will  be  ignited  slowly.  At 
high  speeds  the  strength  of  the  current  being  greater,  causes  the 
charge  to  ignite  more  rapidly — this  charge  produces  an  effect 
equivalent  to  advancing  the  spark. 

In  starting  an  engine  equipped  solely  with  a  magneto,  it  is  necessary 
to  turn  the  crank  much  faster  than  when  a  battery  is  used,  because  the 
armature  must  be  turned  at  a  certain  speed  to  generate  the  required 
current.  Due  to  the  refinement  of  design  this  factor  has  been  reduced 
and  most  magnetos  will  give  a  spark  sufficient  for  ignition  even  if  the 
armature  be  revolved  quite  slowly. 


306 


SELF-PROPELLED    VEHICLES. 


IGNITION.  307 

The  spark  plugs  commonly  used  for  battery  ignition  are  not  well 
adapted  to  a  magneto,  as  the  current  furnished  by  the  latter  is  stronger. 
The  greater  heat  of  the  current  tends  to  burn  the  slender  points  thought 
necessary,  therefore,  with  a  magneto  they  must  be  larger  for  satisfactory 
working.  The  gap  of  a  magneto  plug  should  be  less  than  that  of  a  coil 
plug,  because  the  current,  while  of  greater  amperage  and  heating  value, 
is  of  less  voltage  than  with  a  battery  system.  The  gap  should  not  be 
more  than  one  sixty-fourth  of  an  inch.  The  most  efficient  magneto  plugs 
have  several  points,  so  that  when  the  distance-  between  one  set  becomes 
too  great  the  spark  will  take  place  between  another  set. 

In  magneto  ignition,  an  important  point  is  that  the  revolving  switch 
which  distributes  the  secondary  current,  and  the  contact  breaker  should  be 
kept  clean. 

In  fig.  212  is  illustrated  a  magneto  ignition  system  which  also 
has  a  storage  battery  for  a  second  source  of  current. 

A  Bosch  magneto  is  shown  at  the  left.  It  is  of  the  true  high  tension 
type  but  differs  from  the  standard  rotary  armature  type  in  two  respects, 
i,  the  high  tension  connections  are  slightly  altered,  and  2,  an  additional 
contact  breaker  is  provided  for  the  battery  so  that  the  magneto  will  serve 
also  as  a  timer  for  the  battery,  while  the  secondary  timing  device  on  the 
magneto  is  used  for  both  the  magneto  and  the  battery  current.  All  other 
details  of  the  magneto  are  similar  to  those  of  ordinary  machines. 

For  battery  ignition  a  special  dash  coil  is  provided,  having  a  self-con- 
tained switch  and  button  for  bringing  a  magnetic  vibrator  into  the  circuit 
when  desired.  The  vibrator  is  only  brought  into  operation  for  starting 
the  engine  from  the  seat.  After  starting,  the  vibrator  is  cut  out  and  the 
interruption  of  the  current,  effected  by  mechanical  means,  hence,  there  is 
no  lag  in  the  operation  of  the  interrupter,  as  with  magnetic  vibrators.  If 
there  be  any  mixture  in  the  cylinder,  the  engine  can  be  started  from  the 
seat  by  pressing  the  button. 

The  switch  handle  which  projects  through  a  slot  in  the  casing  of  the 
coil,  locks  in  three  positions  by  a  spring,  the  positions  being  designated 
respectively,  as  "Magneto,"  "Off"  and  "Battery."  The  wiring  connections 
are  as  shown  in  the  illustration. 

Ignition  with  Coil  Spark  Plugs. — In  this  system  the  ignit- 
ing or  firing  device  consists  of  a  combined  spark  plug  and  in- 
duction coil ;  the  latter  being  encased  in  mica  and  hermetically 
sealed.  Outside  this  is  a  metal  cover  that  protects  and  supports 
the  whole.  The  ends  of  the  primary  winding  are  connected  to 
binding  posts  on  top  of  the  casing.  The  two  electrodes  of  the 
plug  form  the  terminals  of  the  secondary  winding.  A  master 
vibrator  and  condenser  are  contained  in  a  separate  box. 

Fig.  213  is  a  wiring  diagram,  showing  the  connections  for  a  four  cylin- 
der engine  fitted  with  coil  spark  plugs.  The  current  supply  may  be  from 
either  battery  or  magneto  as  illustrated.  It  should  be  noted  that  in  the 
wiring,  only  the  primary  circuit  is  exposed.  The  plug  shown  in  the 


308 


SELF-PROPELLED     VEHICLES. 


illustration  has  no  ground  connection  of  the  secondary  terminals,  that  is, 
both  electrodes  are  insulated.  The  connections  of  the  circuit  may  be 
easily  understood  from  the  figure. 

A  modification  of  the  plug  just  described  is  one  having  a  ground  return 
for  both  the  primary  and  secondary  currents.  In  other  respects  the 
wiring  does  not  differ. 

The  advantages  claimed  for  the  coil  plug  system  is  the  elimination  oi 
secondary  leakage  due  to  imperfect  insulation  or  Hertz  wave;  also  ac- 
cessibility secured  by  the  separation  of  coil  and  condenser  and  simplified 
wiring. 

Double  Ignition  Systems. — Some  automobiles  are  equipped 
with  two  independent  means  of  ignition,  having  no  parts  in  com- 
mon, thus  if  anything  happen  to  one  system,  the  other  may  be 
brought  into  use.  Double  ignition  makes  a  delay  on  account  of 
ignition  troubles,  a  remote  probability;  as  a  guard  against  dis- 
ablement, it  is  one  step  farther  than  the  dual  system  in  which 
the  two  modes  of  ignition  are  not  independent. 


U&- 

1 

1 

0 
vituuroR 

.••AShtro                       tjjj 

^  *^                    jAXHflOanff 

FIG.  213. — Wiring  diagram  of  a  coil  spark  plug  system.  There  is  no 
ground  connection  for  the  secondary  terminals;  as  the.be  are  con- 
nected inside  directly  to  the  electrodes  of  the  spark  plug,  both 
elebtrodes  being  insulated.  A  condenser  and  vibrator  are  placed  in 
the  box  shown  at  the  left  of  the  figure.  In  this  system  only  the 
low  tension  wiring  of  the  primary  circuit  is  exposed. 

There  are  many  combinations  to  be  found  in  double  ignition,  one  make 
of  car  being  fitted  with  both  the  make  and  break  and  the  jump  spark 
systems. 


IGNITION. 


309 


Fig.  214  illustrates  the  double  ignition  as  furnished  with  the  Peerless 
cars.  An  Eisemann  low  tension  magneto  is  used  as  one  source  of  current 
supply;  the  current  passes  through  an  induction  coil  on  the  dash,  giving  a 
high  tension  current  at  the  spark  plugs.  In  addition  to  the  magneto  and 
entirely  separated  therefrom  is  the  battery  system.  All  wires  are  connected 
with  their  terminals  by  spring  attachment.  By  means  of  a  rubber  wire  bar, 
the  method  of  wiring  is  improved  with  respect  to  shortening  the  length 
of  wires  and  retaining  them  in  a  desirable  position. 

Another  example  of  double  ignition  is  that  employed  on  the  National 
cars  as  shown  in  fig.  215.  One  system  consists  of  a  synchronous  drive, 
high  tension  magneto,  wired  direct  to  the  spark  plugs ;  the  other  is  com- 
posed of  a  storage  battery,  single  coil  and  distributer. 


FIG.  214. — A  double  ignition  system  with  two  sets  of  spark  plugs  as 
fitted  on  Peerless  cars.  The  current  which  is  furnished  by  an 
Eisemann  low  tension  magneto  passes  through  an  induction  coil  on 
the  dash,  giving  a  high  tension  current  at  the  spark  plugs.  In 
addition  to  the  magneto,  and  entirely  independent  is  a  battery  system 
of  ignition  operating  the  second  set  of  spark  plugs.  The  large 
number  of  connections  necessary  is  somewhat  simplified  by  the  use 
of  a  rubber  wire  bar  as  shown. 


310 


SELF-PROPELLED    VEHICLES. 


Special  Igniting  Devices. — The  fact  that  ignition  could  be 
made  reliable  and  certain,  as  well  as  more  nearly  synchronous,  by 
the  single  spark  as  caused  by  the  magneto,  has  influenced  several 
seekers  after  battery  economy  with  coil  ignition  to  develop  and 
place  on  the  market  devices  in  which  a  single  break  in  the  pri- 
mary circuit  is  caused  mechanically  at  each  instant  at  which 
charge  ignition  is  desired  within  the  several  engine  cylinders. 

These  "single-break"  coil  systems  embody,  in  their  most  highly 


FIG.  215. — Wiring  diagram  for  a  six  cylinder  car,  illustrating  a  double 
ignition  system  with  two  sets  of  spark  plugs.  One  system  consists 
of  a  high  tension  magneto  with  connections  from  its  distributing 
terminals  to  one  set  of  spark  plugs;  a  second  system  is  composed  of 
a  battery,  vibrating  coil,  distributer  and  connections  with  the  second 
set  of  plugs. 

developed  forms,  a  single  plain  coil,  a  secondary  timing  device 
for  the  induced  high  tension  current  and  a  timer  or  circuit- 
breaker  which  causes  a  sharp  break  in  the  circuit  of  the  primary 
coil  winding  each  time  an  ignition  spark  is  required.  After  the 
coil  itself,  the  circuit  breaker  is  the  chief  component  of  single  coil 
systems  with  distributer,  designed  to  produce  but  one  spark  per 


IGNITION.  311 

ignition.  Upon  it  depends  the  effectiveness  of  the  spark,  and  in 
some  measure  also  the  current  consumed  in  the  coil  in  producing 
it. 

In  consideration  of  battery  economy,  it  is  necessary  that  the  circuit 
breaker  make  only  a  sufficiently  long  contact  to  secure  the  proper  building 
up  of  the  magnetic  field  about  the  coil  windings,  before  the  occurrence  of 
the  break.  Because  of  this,  it  is  usual  so  to  set  the  adjustable  point  of 
the  breaker  that  the  contact  duration  is  the  minimum  with  which  a  proper 
igniting  spark  can  be  secured.^  In  single  spark  systems,  the  circuit  is  both 
made  and  broken  by  mechanical  means,  and  there  is  therefore  no  mag- 
netic lag  at  the  period  of  the  break  as  in  vibrator  coils. 

Formerly  dry  cells  gave  satisfaction  with  one  or  two  cylinder  engines, 
but  with  the  advent  of  the  four  and  six  cylinder  engine,  it  was 
found  that  the  increased  current  consumption  caused  the  rapid 
exhaustion  of  the  battery.  On  this  account  the  storage  cell,  of  greater 
first  cost  but  of  longer  life,  was  substituted.  Since  single  break  igniting 
devices  have  been  in  use,  it  has  been  demonstrated  that  with  proper 
treatment  the  dry  cell  battery  can  be  made  to  give  as  good  service  as  can 
any  other  type  of  battery. 

In  view  of  the  increasing  use  of  special  igniting  devices,  a  few  of  these 
will  now  be  described. 

Atwater  Kent  Spark  Generator. — This  device  produces  one 
contact  only  for  each  ignition.  The  duration  of  this  contact  is 
just  long  enough  to  enable  the  coil  to  build  up  for  the  desired 
length  of  spark,  and  it  is  the  same  whether  the  engine  runs  fast 
or  slow.  By  turning  the  contact  screw,  which  is  the  only  thing 
adjustable  about  the  apparatus,  the  duration  of  contact  may  be 
varied  within  limits,  and  a  longer  or  shorter  spark  produced  at 
will. 

Briefly  described  the  Atwater  Kent  device  consists  of  the  fol- 
lowing elements: 

(a)  A  non-vibrator  jump  spark  coil  of  highly  efficient  and 
durable  construction.  (&)  Condenser,  (c)  Mechanical  con- 
tact maker  in  the  primary  circuit,  driven  by  suitable  connection 
from  the  engine.  (</)  High  tension  distributer.  (e)  Spark 
advancing  device.  (/)  Button  for  starting  "on  the  spark."  (g) 
Individual  cut-outs  for  testing  the  cylinders  separately. 

Of  these  elements,  the  contact  maker,  distributer,  and  spark  advancer 
are  carried  by  a  single  vertical  shaft,  which  runs  in  the  left-hand  side  of 
the  case  containing  the  coil  and  condenser.  This  case  is  bolted  on  the 
dash,  in  easy  reach  of  the  driver,  and  the  general  arrangement  is  shown 
in  Fig.  216-1. 

The  mechanism  by  which  the  primary  contact  is  made*  is  illustrated  in 
figs.  216-2  and  216-3  which  show  a  plan  view  of  the  contact  maker  and  por- 


319 


SELF-PROPELLED    VEHICLES. 


tions  thereof  with  the  cover  removed  and  the  shaft  in  different  positions. 
The  moving  parts  are  the  shaft  itself,  A,  fig.  217,  the  snapper  B,  and  the 
pivoted  contact  arm  C. 

The  shaft  carries  four — or  six  for  a  six  cylinder  engine — milled  notches, 
forming  a  ratchet  which  engages  the  claw  at  the  end  of  the  snapper. 
The  latter,  which  is  shown  separately  in  fig.  217  is  a  light  piece  of 
tempered  steel  which  is  guided  by  slots  in  the  bronze  base  DE,  and  is 


H 


FIG.  216.— 1— The  Atwater  Kent  spark  generator.  2  and  3 — sectional 
views  showing  two  positions  of  the  contact  maker.  This  device  is 
designed  especially  to  secure  economy  in  the  use  of  the  current  and 
is  adapted  to  operate  with  a  dry  battery.  The  generator  comprises 
the  following  elements:  1,  a  plain  secondary  coil;  2,  condenser; 
3,  contact  maker;  4,  secondary  distributer;  5,  spark  advancing 
device;  6,  starting  button;  7,  individual  cut  outs  for  testing  the 
cylinders  separately. 

pulled  by  the  spring  F,  against  a  spring  wire  stop  G,  when  released  from 
engagement  with  the  notches  on  the  shaft.  The  contact  arm  C,  is  likewise 
held  normally  in  the  position  shown  by  the  tension  of  spring  H. 

The  shaft,  turning  counter  clockwise,  draws  the  snapper  into  the  position 
shown  in  Fig.  216-2,  and  the  claw  of  the  snapper  when  released  rides 
up  on  the  rounded  part  of  the  shaft  as  shown  in  Fig.  216-3  acting  thereby 
as  a  wedge  between  the  shaft  and  the  steel  hook  I  of  the  contact  arm, 


IGNITION. 


313 


which  is  pivoted  at  J.  The  contact  arm  is  thus  oscillated  to  produce  con- 
tact between  a  platinum  point  in  the  flat  copper  spring  K,  and  the 
stationary  insulated  contact  screw  I* 

As  the  snapper  continues  its  motion,  it  releases  the  hook  I,  thereby 
permitting  the  contact  arm  to  rebound  and  break  contact.  The  snapper 
then  comes  to  rest  in  its  normal  position,  Fig.  217  and  the  contact  arm 
resumes  its  position  of  rest  against  the  stop.  With  the  engagement  of  the 
snapper  by  the  next  tooth  of  the  ratchet,  the  process  is  repeated. 

The  timing  device  is  shown  in  Fig.  216-1.  The  brass  blades  which  deliver 
the  secondary  current  to  the  cable  terminals  are  insulated  from  the  rest 
of  the  shaft;  and  the  terminals  themselves  are  protected  by  weather-proof 
insulation.  As  the  blades  do  not  touch  the  terminals,  there  is  no  wear. 
Opposite  each  terminal  is  an  outside  spring  button,  by  pressing  which 
the  spark  may  be  grounded  for  testing  the  cylinders. 

Ignition  is  advanced  or  retarded  by  means  of  a  spiral  sleeve  beneath 
the  case,  which  rotates  the  upper  portion  of  the  shaft  through  a  suitable 
angle.  To  start  "on  the  spark,"  the  button  B,  Fig.  216-1  is  pressed.  This 
short  circuits  the  contact  maker  and  produces  a  spark  in  the  cylinder  in 
communication  with  the  distributer  at  the  time. 


FIG.  217. — Contact  maker  of  Atwater  Kent  spark  generator.  The  moving 
parts  are  the  shaft,  A,  the  snapper  B,  and  the  pivoted  contact  arm 
C.  The  shaft  carries  four — or  six  for  a  six  cylinder  engine — milled 
notches  forming  a  ratchet  which  engages  the  claw  at  the  end  of 
the  snapper  B.  The  operation  of  the  device  is  explained  in  the  text. 

Pittsfield  Acme  Igniter. — An  outside  coil  is  employed  with 
this  device,  but  it  is  designed  for  attachment  to  the  timer  shaft 
in  place  of  the  ordinary  timer.  The  period  of  contact  is  con- 
stant and  independent  of  the  speed  of  the  engine.  A  cam  serves 
to  actuate  the  circuit  breaker  parts,  and  the  constant  period  of 


314 


SELF-PROPELLED    VEHICLES. 


contact  is  secured  through  causing  the  movable  contact  point  to 
oscillate  under  the  influence  of  a  pair  of  flat  springs ;  after  its  re- 
lease by  the  cam. 

The  action  of  the  oscillating  parts  will  be  the  same  no  matter  at  what 
speed  the  actuating  cam  is  run,  since  contact  is  made  and  broken  by  the 
action  of  these  flat  springs  after  the  cam  has  released  the  breaker  point 
carrying  part.  The  cam  simply  compresses  one  of  the  springs,  and  the 
circuit  is  both  wade  and  broken  by  spring  action  alone.  The  distributer 
rotor  is  driven  by  the  circuit  breaker  rotor  and  is  mounted  within  an 
upper  insulating  part  which  fully  encloses  the  circuit  breaker. 


=±=-    GROUND 


3=r-  GROUND 


PlO.  218.— -The  Perfex  ignition  system.  The  Igniters  consist  of  coll  spark 
plugs,  each  haying  one  electrode  grounded.  A  box  shown  to  the  left 
contains  the  vibrator  and  condenser.  In  this  method  of  ignition  the 
primary  wiring  only  is  exposed. 

American  Igniter. — In  the  operation  of  this  igniter  no  ex- 
ternal coil  is  used.  It  is  intended  for  mounting  on  the  tinier 
shaft  in  the  usual  manner.  The  body  consists  of  a  cylindrical, 
insulating,  enclosing  part  into  which  the  secondary  coil  winding 
fits.  The  latter  is  formed  up  on  a  spool  of  insulating  material, 
and  its  connections  are  made  through  metal  blocks  which  register 
in  the  case  and  complete  the  secondary  circuit  without  the  use 
of  binding  posts.  The  coil  core  is  a  hollow  cylinder  of  iron 
wires,  and  the  primary  winding  surrounds  it,  the  two  forming 
an  integral  part  of  the  before  mentioned  body  casing. 

The  circuit  breaker,  of  the  single  break  type  is  mounted  on  the  under 
face  of  the  body  and  operated  by  a  multiple  cam  self  contained  with 
the  ignitor  shaft,  which  latter  is  carried  in  annular  ball  bearings.  The 
cam  operates  against  a  roller  ended  lever  which  carries  a  contact  point 
This  point  makes  the  circuit  fhrough  a  second  point  carried  by  an  adjust- 
able screw.  The  point  itself  telescopes  into  the  adjusting  screw  and  is 
backed  by  a  light  spring.  This  construction  causes  the  light  spring  to  be 
compressed  by  the  action  of  the  cam,  and  increases  the  speed  of  the  parts 
at  the  instant  of  the  break,  since  the  break  proper  is  made  at  a  point  about 
midway  in  the  travel  of  the  breaker  lever,  when  its  speed  is  highest 


IGNITION.  315 

Ignition  Troubles. — To  successfully  cope  with  ignition  trou- 
bles there  are  two  requisites,  I,  a  thorough  knowledge  of  the 
system  used  and,  2,  a  well  ordered  course  of  procedure  in  looking 
for  the  source  of  trouble.  In  many  ignition  systems,  the  chief 
difficulty  encountered  in  the  location  of  defects  arises  from  the 
fact  that  faults  in  different  portions  of  the  circuit  sometimes  make 
themselves  manifest  by  the  same  symptoms.  If  each  defect  had 
its  individual  symptom,  locating  the  trouble  would  be  compara- 
tively easy,  but  as  it  is,  it  is  sometimes  quite  difficult  to  find  the 
defective  parts.  In  general  the  following  method  should  be 
adopted  to  locate  possible  derangements: 

1.  Examine  the  source  of  current  supply;  if  a  battery,  test  each  cell 
separately  and  remove  any  found  to  be  weak.    When  a  magneto  is  used, 
disconnect  the  drive  and  turn  armature  by  hand,  if  the  field  magnets  have 
not  lost  their  strength  the  armature  should  turn  perceptibly  hard  during 
certain  portions  of  each  revolution. 

2.  Examine  the  primary  circuit  for  breaks  in  its  continuity,  see  that  all 
connections  are  bright  and  firmly  held  together  by  the  binding  screws; 
the  timer  contacts  should  be  clean. 

3.  The  spark  plug  points  should  be  clean  and  the  air  gap  the  proper 
length — about  one  thirty-second  of  an  inch. 

4.  See  that  the  vibrator  contacts  are  in  good  condition  and  the  adjust- 
ment correct.     With  this  preliminary  examination  the  system  may  now 
be  tested. 

Testing. — Remove  the  spark  plug  and  lay  it  on  the  cylinder 
without  disconnecting  the  lead  to  the  insulated  electrode;  the 
body  of  the  plug  only  should  touch  the  metal  of  the  cylinder. 
Crank  the  engine  and  note  if  a  spark  passes  at  the  gap.  The 
spark  should  be  "fat"  if  everything  be  in  good  condition ;  if  a 
weak  spark  be  produced  it  may  be  due  to  either  a  loose  terminal, 
run  down  battery  or  badly  adjusted  vibrator.  When  no  spark 
can  be  obtained  the  entire  system  must  be  examined  and  tested, 
beginning  at  the  battery.  In  a  multi-cylinder  engine  a  faulty 
spark  plug  may  be  located  as  follows : 

Remove  the  nuts  from  the  top  of  the  plugs,  leaving  the  high  tension 
wires  upon  them.  Start  the  engine,  and  then  disconnect  and  ground  all 
wires  except  one,  then  run  the  engine  on  one  cylinder  only.  If  after  a 


316 


SELF-PROPELLED     VEHICLES. 


good  test  at  various  engine  speeds,  no  misfiring  occur,  it  can  be  taken 
for  granted  that  the  plug  is  sound.  Proceed  in  this  manner  with  the 
remaining  plugs. 

When  a  multi-unit  coil  is  used,  a  faulty  plug  may  be  located  by  holding 
down  all  the  vibrator  blades  but  one  so  that  only  one  spark  plug  operates. 
By  running  each  cylinder  separately  by  this  means  it  can  easily  be  ascer- 
tained which  plug  is  defective.  Some  coils  are  provided  with  little  knobs 
for  cutting  out  cylinders  in  the  manner  just  described. 

Breaks  in  the  Wiring. — An  entire  break  is  more  easily  found 
than  a  partial  one.  To  test  for  an  entire  break,  place  the  engine 
upon  the  sparking  point,  close  primary  switch  and  touch  the  two 


FIG.  219. — Section  through  the  Simms-Bosch  high  tension  magneto.  A, 
armature  shaft;  B,  curved  arm  carrying  high  tension  lead;  C,  lug 
supporting  screw;  D,  adjusting  contact  breaker,  E,  against  spring, 
F;  G,  revolving  sleeve  carrying  face  cams;  H,  high  tension  lead 
wire;  J,  carbon  brush  of  distributer  disc;  K,  insulated  ring;  L, 
rotating  drum  of  distributer;  M  and  N.  distributer  brushes;  O  and 
P,  safety  spark  gap;  Q,  swiveled  lever  for  retarding  or  advancing  the 
spark  time;  R,  condenser;  T,  T,  spring  pushed  wick  oilers  for 
armature  spindle. 

terminals  of  the  suspected  wire  with  a  test  wire.  A  flow  of  cur- 
rent indicates  a  break.  A  partial  break,  or  one  held  together  by 
the  insulation  may  sometimes  be  located  by  bending  the  wire 
sharply  at  successive  points  along  ;ts  length,  the  engine  being  at 
the  sparking  point  and  the  switch  closed  as  before. 


IGNITION. 


317 


Primary  Short  Circuits. — Disconnect  the  primary  wires  from 
the  coil,  leaving  the  ends  out  of  contact  with  anything.  Now 
touch  the  switch  points  momentarily,  if  any  spark  appear  there 
is  a  short  circuit.  A  short  circuit  may  sometimes  be  removed  by 
clearing  all  wires  of  contact  with  metallic  bodies  and  by  pulling 
each  wire  away  from  others  which  were  formerly  in  contact  with 
•t. 


CISTB16UTOU   DISC 


FIG.  220. — Circuit  Diagram  showing  the  Simms-Bosch  high  tension 
magneto  wired  up  to  spark  a  four  cylinder  engine.  The  secondary 
current  as  led  from  the  armature  winding  by  a  wire,  encased  in  a 
curbed  tube,  which  emerges  from  the  spindle  of  the  armature. 
Thence,  through  a  carbon  brush  bearing  iipon  a  flat  brass  ring,  on 
the  front  of  the  secondary  distributer,  it  passes  to  the  contact 
segment;  being  conveyed  to  each  spark  plug  in  turn  through  the 
four  brushes  of  the  secondary  distributer.  All  these  details  may  be 
readily  learned  by  reference  to  the  diagram  of  circuits. 


Secondary  Short  Circuits. — Disconnect  the  secondary  lead 
from  spark  plug.  Under  this  condition  the  high  tension  current 
may  sometimes  be  heard  or  seen  discharging  from  the  secondary 
wire  to  some  metallic  portion  of  the  car.  Water  in  contact  with 
the  secondary  wire  will  sometimes  cause  a  short  circuit  unless 
the  insulation  be  of  the  best  quality. 


318  SELF-PROPELLED     VEHICLES. 

The  Primary  Switch. — This  portion  of  the  primary  circuit 
sometimes  causes  trouble  by  making  poor  contact.  This  is  gen- 
erally due  to  the  deterioration  of  the  spring  portion  of  the  metal 
which  gradually  loses  its  resiliency.  Snap  switches  somtimes  fail 
through  the  weakening  of  the  springs  which  hold  them  in  the 
"on"  or  "off"  position.  The  contacts  of  a  switch  should  be  kept 
in  good  condition. 

Primary  Connections. — All  binding  posts  and  their  connec- 
tions should  be  clean  and  bright.  The  wires  should  be  firmly 
secured  to  the  binding  posts,  as  a  loose  connection  in  the  primary 
circuit  is  often  the  cause  of  irregular  misfiring  or  the  stopping 
of  the  engine. 

Vibration. — Since  the  wires  are  subject  to  constant  vibration, 
a  number  of  strands  of  fine  wire  is  better  than  a  single  heavy 
wire,  as  the  latter  is  more  liable  to  be  broken.  In  securing  the 
wire  to  a  binding  post  care  should  be  taken  that  all  the  strands 
are  bound,  as  a  leak  will  result  if  a  single  strand  come  in  contact 
with  any  uninsulated  metal. 

Timers. — The  revolving  part  of  a  timer  may  not  make  good 
contact  with  the  stationary  segments  on  account  of  insufficient 
pressure  or  dirt :  take  timer  apart,  thoroughly  clean  and  increase 
the  spring  pressure,  if  necessary. 

Distributers. — These  may  give  trouble  by,  i,  presence  of  dirt, 
2,  loose  contacts  or,  3,  division  of  the  spark ;  this  latter  effect  is 
sometimes  caused  by  metallic  particles  wearing  off  the  revolving 
part  forming  a  path  so  that  the  spark  passes  from  the  revolving 
part  to  more  than  one  contact  segment. 

Coils. — The  part  of  a  coil  which  requires  most  frequent  atten- 
tion is  the  vibrator.  The  contact  points  are  subject  to  deteriora- 
tion on  account  of  the  small  spark  always  present  between  the 
points  when  the  coil  is  in  operation.  In  time,  the  points  become 
corroded  and  burned,  and  therefore  require  to  be  re-surfaced  by 
smoothing  with  a  fine  file. 


•*" BATTC«V 


FIG.  221. — A  device  for  testing  ignition  advance  to  illustrate  the  effect 
of  lag  in  vibrating  spark  coils.  The  higher  the  engine  speed  the 
more  the  spark  can  be  advanced,  but  no  such  advance  is  possible  as 
would  be  indicated  by  the  position  of  a  timer  apparently  capable  of 
a  movement  of  90  degrees  or  more.  This  great  amount  of  advance 
of  the  timer  is  necessary  to  overcome  the  enormous  lag  in  vibrating 
spark  coils,  as  it  takes  just  as  long  to  start  vibrating,  whether  the 
engine  be  running  100  or  2,000  revolutions.  The  instrument,  as  shown 
above,  for  demonstrating  this  advance  spark  theory  consists  of  a 
model  of  a  gas  engine  with  its  cylinder  and  piston,  connecting  rod 
and  crank,  but  secured  to  the  crank  pin  is  a  small  pointer  K,  which 
rotates  within  a  metal  ring  L,  clearing  it  about  Y*  inch.  The  wires 
from  the  secondary  of  the  spark  coil  are  connected  to  the  insulated 
metal  ring  L.  and  to  the  crank  and  pointer  K,  so  the  spark  will 
jump  from  the  pointer  K  to  the  ring  L,  while  the  engine  is  in  opera- 
tion. The  timer  should  be  set  in  such  a  position  that  in  turning 
over  the  engine  slowly  by  hand  in  the  direction  shown  by  the  dotted 
lined  crank  a  spark  will  be  produced  when  the  crank  is  at  the  dead 
centre.  If  the  engine  be  now  speeded  to  1,000  revolutions  per  minute 
without  moving  the  timer,  the  spark  will  jump  across  at  B  or.  in 
other  words,  will  be  90  degrees  late.  This  lateness  of  the  spark  is 
entirely  due  to  the  mechanical  lag  of  the  vibrator  and  the  magnetic 
lag  of  the  iron  core;  hence,  the  timer  must  be  advanced  an  equiv- 
alent amount  to  balance  up  the  two.  By  varying  the  speed  of  the 
engine  the  spark  moves  from  the  position  A'  to  B'. 

319 


320  SELF-PROPELLED    VEHICLES. 

A  faulty  connection  to  the  condenser  is  at  once  shown  by  large 
sparks  at  the  vibrator  points.  Any  repairs  to  a  coil,  aside  from 
the  vibrator  should  be  done  by  an  expert  as  the  construction  is 
very  delicate. 

Igniters. — In  make  and  break  ignition,  failure  to  get  a  spark, 
especially  with  a  weak  battery,  is  frequently  due  to  the  tappet 
spring.  This  spring  must  be  quite  stiff  so  as  to  cause  the  break 
to  take  place  with  considerable  rapidity — the  more  rapid  the 
break,  the  better  is  the  quality  of  the  spark.  The  contact  points 
of  the  igniter  electrodes  are  subject  to  corrosion  and  wear.  When 
they  become  pitted  the  contact  surfaces  should  be  filed  smooth. 

Spark  Plugs. — Repeated  failure  to  start  when  the  coil  vibrator 
operates  indicates  a  faulty  spark  plug.  A  rich  gasoline  mixture 
often  leaves  a  carbon  deposit,  and  being  a  partial  conductor 
short  circuits  the  plug.  The  porcelain  insulation,  on  account  of 
its  brittleness,  may  crack  inside  the  sleeve  allowing  a  spark  to 
pass  there  instead  of  at  the  gap.  Mica  insulation  sometimes 
becomes  saturated  with  oil  causing  the  layers  to  separate,  per- 
mitting a  short  circuit. 

Engine  Misfires  and  Finally  Stops. — This  may  be  due  to  the 

exhaustion  of  the  battery  and  is  indicated  by  a  weak  spark  and 
very  faint  vibrator  action. 

Engine  Suddenly  Stops. — This  is  generally  caused  by  a 
broken  wire  or  loose  switch  which  does  not  stay  closed.  If  the 
engine  has  only  one  cylinder,  the  broken  wire  may  be  either  in 
the  primary  or  secondary  circuit ;  if  a  multi-cylinder  engine,  the 
break  is  in  the  primary  circuit. 

Engine  does  not  Start. — Usually  caused  by:  (a)  primary 
switch  not  closed,  (b)  battery  weak  or  exhausted,  (c)  entire  or 
partial  break  in  wire,  (d)  loose  terminal,  (e)  moisture  on  spark 
plug,  (f)  fouled  plug,  (h)  spark  too  far  retarded  or  advanced, 
(i)  with  magneto  ignition,  too  slow  cranking. 

Engine  runs  Fitfully. — Frequently  results  from  a  partial 
break  in  the  wiring,  especially  in  the  primary  circuit. 


IGNITION. 


Pre=ignition. — Caused  by  (a)  some  small  particle  in  the  cylin- 
der becoming  heated  to  incandescence  (b)  the  electrodes  of  the 
spark  plug  becoming  red  hot,  (c)  intermittent  short  circuit  in  the 
primary. 

Engine  runs  with  Switch  Open. — Usually  caused  by,  (a) 
overheated  engine  or  plug  points,  (b)  primary  short  circuit,  (c) 
defective  switch,  (d)  an  incandescent  particle  inside  the  cylinder. 


FIG.  222. — Wiring:  diagram  for  a  four  cylinder  car,  illustrating-  a  double 
ignition  system  with  two  sets  of  spark  plugs.  A  high  tension 
magneto  is  connected  through  its  distributing  terminals  to  one  set  of 
plugs  and  current  from  a  battery  passes  through  a  single  vibrating 
coil  and  distributer  to  the  second  set,  thus  furnishing  two  in- 
dependent systems. 

Engine  Misfires. — This  may  be  caused,  by  (a)  weak  battery, 
(b) partial  break  in  conductor,  (c)  loose  or  disconnected  termi- 
nal,  (d)  intermittent  short  circuit  in  the  secondary,  (e)  faulty 
action  of  either  timer  or  vibrator  contacts,  (f)  bent  vibrator 
blade,  (g)  faulty  spark  plug,  (h)  air  gap  too  large. 

Knocking  of  Engine. — Too  much  advance  of  the  spark  some- 
times produces  this  effect. 


322  SHLr-PROPELLHD     rF.HICLES. 

Loss  of  Power  without  Misfires. — This  may  be  due  to  badly 
adjusted  coil  contacts,  poor  spark  or  incorrect  timing. 

Explosions  in  the  Muffler. — These  are  usually  caused  by  mis- 
firing, partially  charged  storage  battery  or  by  one  cylinder  not 
working. 

Knocking  in  the  Cylinder. — The  form  of  unusual  noise  com- 
monly described  as  "knocking"  consists  of  a  regular  and  continu- 
ous tapping  in  the  cylinder,  which  is  so  unlike  any  sound  usual 
and  normal  to  operation  that,  once  heard,  it  cannot  be  mistaken. 
Too  much  advance  of  the  spark  sometimes  produces  this  result. 

If  retarding  the  spark  from  the  extreme  lead  fails  to  overcome 
the  knock,  the  mixture  may  be  throttled  with  good  probability  of 
success.  As  mentioned  by  numerous  authorities,  the  placing  of 
the  spark  plug  in  the  exact  centre  of  the  combustion  space  occa- 
sions a  peculiarly  sharp  knock,  which  may  be  stopped  by  advanc- 
ing or  retarding  the  spark  from  the  one  point  of  trouble.  This 
explanation  of  the  trouble  is  questioned  by  others,  and  is  probably 
over-rated. 


DIAGRAM  OF  THE  CRANKS  A> 


Twin  Cy/incfer  Crc?/7frs-360 


Dou6/e  Oppose 


four  Cy//s?tf 


In  the  diagrams  of  this  plate  are  shown  the  arrangements 
of  the  cranks  of  a  two-cylinder  vertical,  a  two-cylinder  opposed, 
a  three,  a  four  and  a  six-cylinder  gasoline  engine,  most  suited 
for  maintaining  perfectly  balanced  operation.  In  the  two- 
cylinder  vertical  the  cranks  are  set  in  one  line,  or  at  360°.  In 
the  double-opposed,  the  cranks  are  set  at  180°,  but,  as  may  be 
understood  from  the  diagram,  the  two  in-strokes  and  two  ont- 
Btrokes  on  the  two  cylinders  are  contemporaneous,  as  in  the 
vertical  two-cylinder  engine.  The  four-cylinder  engine  has  the 
cranks  at  180°,  the  first  and  fourth  being  at  360°  relatively,  or  in 
im«  line,  and  the  second  and  third  also  at  SOT0  relatively,  or  on 


one  line.   The  three  and  slx-c 
at  120°  apart. 

The  operative  cycles,  or  1 
in  the  cylinders  of  the  severs 
in  the  circular  diagrams.  He 
stroke  in  one  cylinder  of  a  t 
aneous  with  the  suction  str< 
cylinder  engine  the  explosion 
poraneous  with  the  exhaust, 
lively,  in  three  other  cylindi 
the  exclusion  stroke  in  one  i 


CYCLES  OF  MULTIPLE-CYLINDER  ENGINES. 

/      2      3 


Cranks -/8O 


Three  Cy/i/rfer  Cranks -/2O 
rtrecf 


5» 


.er  engines  have  the  cranks 

accessions  of  cycular  events 
rieties  of  engines,  are  shown 
a  may  be  seen,  the  explosion 
ylinder  engine  is  contempor- 
n  the  other.  In  the  four* 
ke  in  one  cylinder  is  contem- 
io  and  compression,  respec- 
In  the  three-cylinde^  engine 
der  is  contemporaneous  with 


two-thirds  of  an  exhaust  stroke  in  another  cylinder,  with  two. 
thirds  of  a  compression  stroke  in  the  third  cylinder,  and  with 
one-third  of  a  suction  stroke  in  both,  an  interval  of  one-third 
stroke  intervening  between  the  power  strokes.  In  the  six- 
cylinder  engine,  an  explosion  stroke  in  one  cylinder  is  contem- 
poraneous with  one-third  of  an  explosion  stroke  in  two  other 
cylinders,  as  shown  in  the  diagram.  In  all  the  diagrams,  O 
indicates  a  compression  stroke ;  E,  an  exhaust  stroke ;  S,  a 
suction  stroke ;  and  the  shaded  arcs,  the  duration  of  the  ex- 
plosion  or  power  strokes  in  the  several  cylinders. 


CHAPTER  TWENTY-SIX. 

BAI.ANCING     GASOLINE     ENGINES. 

Balancing  Gasoline  Engines. — An  important  item  in  the 
operative  efficiency  of  any  type  of  engine  is  balance.  This  in- 
volves some  mechanical  means  for  rendering  all  movements 
perfectly  even  and  for  neutralizing  thrusts  and  vibration.  Bal- 
ance is  particularly  necessary  in  an  internal-combustion  engine 
of  any. type,  since,  with  a  power  effort  applied  only  at  stated  in- 
tervals, instead  of  continually,  as  in  a  steam  engine,  there  is  a 
far  greater  likelihood  of  irregularity  at  some  point  in  the  cycle. 
The  most  probable  results  of  unbalanced  movement  in  a  gas  en- 
gine will  be : 

1.  Vibration,    with   attendant   wear  on   the   supports  of  the 
engine. 

2.  Wear  on  the  moving  parts,  as  between  the  piston  and  cylin- 
der bore  and  at  the  bearings  of  the  shafts.     This  must  sooner 
or  later  result  in  the  disablement  of  the  engine. 

3.  Loss  of  efficiency,  on  account  of  the  creation  of  numerous 
stresses  which  absorb  power. 

Causes  of  Unbalanced  Motion. — The  problem  of  properly 
balancing  an  internal-combustion  engine  has  always  been  serious, 
and  considerable  ingenuity  has  been  exercised  in  the  effort  to 
achieve  a  perfect  solution.  The  effort  to  transform  reciprocating 
into  rotary  motion  must  inevitably  be  attended  by  strains  and 
vibration,  which,  when  proper  adjustments  are  absent,  result  in 
wear  on  the  bearings  and  deformation  of  the  cylinder  bore.  In 
a  single-cylinder  gas  engine  the  vibrations  resulting  from  inertia 
of  the  moving  parts,  moving  under  varying  stress  through  the 
several  stages  of  the  cycle,  are  liable  to  be  excessive.  It  is  neces- 
sary, therefore,  to  provide  some  means  for  compensating  this 
irregularity,  so  that,  as  far  as  possible,  the  active  energies  may 
be  equalized. 

323 


324 


SELF-PROPELLED   VEHICLES. 


Balancing  a  SingIe=CyIinder  Engine. — Very  few  single-cyl- 
inder gas  engines  have  been  constructed  with  more  than  an  ap- 
proximate balance.  This  is  true  because  the  only  available 


PiO.  223. -Section  of  the  De  Dion  and  Bouton  Single-Cylinder  Water-Jacketed  Car 
riage  Engine.  Parts  are  as  follows:  A,  crank  case  formed  by  two  cylindrical 
pieces  bolted  together;  B,  the  inlet  valve  for  the  fuel  mixture  from  tlie  carbu- 
retter ;  C,  the  exhaust  valve,  held  closed  by  a  helical  spring,  F,  and  opened  by 
the  cam,  H ;  D,  the  opening  for  the  compression  tap ;  E,  the  threaded  hole  for  the 
sparking  plug;  F,  the  spring  on  the  exhaust  valve  rod;  G,  the  cylinder;  I,  ihe 
port  of  exit  for  the  jacket  water  from  jacket,  J,  the  inlet  being  at  a  point  near 
the  base  of  the  jacket;  K  and  K  are  the  flywheels,  or  crank  discs,  which  are 
Joined  together  as  shown,  by  the  crank  pin,  N  ;  M  is  the  connecting  rod ;  N  is  the 
crank  pin ;  O  and  O  are  the  crank  shafts,  that  on  the  right  carrying  the  pinion, 
P,  that  on  the  left  being  threaded  for  connection  to  the  driving  gear:  P  is  a 
pinion  on  the  crank  shaft  meshing  with  gear,  Q. 

method  is  to  set  balance  weights  opposite  the  crank  pin ;  and  to 
make  balance  weights  balance  is  a  very  delicate  problem.     In 


BALANCING  GASOLINE  ENGINES 


325 


general,  the  proper  weight  to  be  used  for  good  balance  must  be 
equal  to  the  weight  of  the  moving  parts  to  which  it  is  opposed. 
According  to  the  generally  accepted  theory,  the  weights  to  be 


FIG.  224. — The  Mitchell  Four-Cylinder  Engine.  Sectional  view,  showing: 
front  of  engine  and  cross  section  of  cylinder.  The  valve  action  is 
direct  for  the  intake  valves.  An  overhead  rocker  for  the  exhaust 
valve  is  placed  in  a  cage  in  the  middle  of  a  cylinder  head.  The 
rocker  is  worked  by  a  vertical  push  rod,  having  its  lower  end 
dropped  into  a  cup  in  the  top  end  of  the  cam  roller  carrying  lifter. 

considered  are  those  of  the  crank  and  crank  pin,  together  with  a 
certain  portion  of  the  weight  of  the  connecting  rod.  In  deter- 
mining the  correct  portion  of  the  weight  to  be  used,  the  method 


326  SELF-PROPELLED   VEHICLES, 

usually  followed  is  to  set  the  piston  end  of  th<-  ;d  jn  a  knife- 
edge  support  and  to  hang  the  opposite  or  crank  end  to  a  spring- 
scale  balance.  This  weight,  which  will  naturally  be  smaller  than 
that  of  the  connecting  rod  wholly  supported  by  the  balance,  may 
be  taken  as  the  greatest  weight  that  is  mechanically  significant. 

Arrangement  of  the  Cranks. — It  may  be  safely  said,  that  for 
success  in  balancing  a  single-cylinder  vehicle  engine,  De  Dion  & 
Bouton,  of  France,  stand  almost  alone.  In  other  carriages  than 
theirs,  especially  those  of  American  manufacture,  vibration  was 
at  one  time  an  almost  inevitable  feature.  This  trouble  early  led 
to  the  construction  of  motors  with  several  cylinders.  Daimler's 
V-shaped  double-cylinder  engine  was  nearly  the  first  meritorious 
attempt  to  balance  the  moving  parts  of  two  cylinders.  It  con- 
sisted of  two  cylinders  inclined  from  the  vertical,  so  as  to  form 
an  angle  of  about  30  degrees  with  the  connecting  rods  working  on 
a  common  crank.  Later  on,  Daimler  engines  were  made  with  two 
vertical  parallel  cylinders,  with  cranks  at  180  degrees.  This  ar- 
rangement soon  proved  ineffective  to  prevent  vibration,  and,  as  a 
consequence,  the  common  crank  was  restored,  both  pistons  mak- 
ing their  out-strokes  and  in-strokes  simultaneously. 

Proportions  of  the  Bore  and  Stroke. — Another  element  of 
design  that  undoubtedly  contributes  largely  to  the  end  of  attain- 
ing balanced  operation  is  the  proper  proportioning  of  the  parts. 
The  superior  balance  of  the  De  Dion  single-cylinder  engine  is 
to  be  attributed  to  the  fact  that  the  stroke  is  short,  in  proportion 
to  the  diameter  of  the  cylinder,  quite  as  much  as  to  the  adjustment 
of  moving  weights.  Very  many  carriage  engines  have  the  stroke 
length  and  diameter  of  bore  approximately  equal,  while  in  few 
of  them  is  the  stroke  very  much  the  longer. 

Double=Piston  Cylinders. — In  addition  to  adjustment  of  mov- 
ing weights,  several  engines  have  been  designed  to  balance  the 
reaction  produced  by  explosion  of  the  charge  by  the  use  of  two 
pistons  in  one  cylinder,  set  face  to  face,  so  that  both  are  forced 
outward  by  the  power  impulse.  In  such  engines,  of  which  the 


BALANCING  GASOLINE  ENGINES. 


327 


Gobron-Brillie  is  a  type,  approximate  freedom  from  vibration  is 
accompanied  by  two  other  advantages — greater  velocity  of  ex- 
pansion, with  consequently  greater  speed,  and  immunity  from 
leakage,  due  to  joints  and  gaskets  in  the  cylinder. 

The  De  Dion  Two-Cylinder  Engine. — One  of  the  most  no- 
table attempts  to  neutralize  vibration  in  a  four-cycle  engine  is  the 
De  Dion  balanced  double  cylinder.  In  this  engine  the  two  cylin- 
ders make  their  out-strokes  and  in-strokes  contemporaneously,  as 
in  other  double-cylinder  engines.  Balance  is  secured,  however, 


»'/i9;M/j/M>;sss;MSMS:iwjjsJ7 
_=== 


FIG.  225. -The  Gobron-Brillie  Two-CyJinder,  Four-piston  Balanced  Engine. 

by  the  use  of  a  third  cylinder,  in  which  slides  a  piston,  equal  in 
weight  with  its  connecting  rod  to  the  weights  of  the  moving  parts 
in  the  other  two.  This  third  cylinder  performs  none  of  the 
functions  of  power  production,  its  sole  purpose  being  balance  of 
motion.  The  crank  or  the  third  piston  is  set  at  180  degrees  to  the 
other  two.  According  to  published  statements,  excellent  results 
were  attained  in  practice  with  this  engine. 


328 


SELF-PROPELLED    VEHICLES 


BALANCING  GASOLINE  ENGINES. 


329 


The  Three-Cylinder  Engine. — The  three-cylinder  engine, 
having  its  cranks  set  at  120°  has  been  used  on  several 
motor  vehicles,  and  has  proven  itself  an  improvement  on  either 
the  single  or  double  cylinder,  in  point  of  easily-achieved  balance 
of  the  working  parts.  The  single-cylinder  engine  has  a  power 
stroke  in  each  two  revolutions  of  the  fly-wheel,  and  the  double- 
cylinder,  in  each  revolution.  In  the  three-cylinder  engine,  how- 
ever, a  power  stroke  begins  at  each  240°  of  rotatio^  or  three 
power  strokes  to  a  complete  cycle  of  two  revolutions  as  shown 
in  the  accompanying  folder  diagram. 


FIG.  227. — Sectional  view  of  the  Maxwell  double  opposed  motor.  Cylin- 
ders 4l/2  by  4,  rated  at  fourteen  horse-power  at  normal  speed.  The 
valve  cams  and  cam  shaft  are  contained  in  a  separate  frame  which 
can  be  removed  without  change  of  timing. 

The  strain  put  upon  the  fly-wheel  in  compressing  the  charge 
to  the  high  point  used  in  many  modern  engines,  must  be 
disturbing  to  perfectly  even  running,  unless  the  fly-wheel 
be  very  heavy  and  extremely  well  calculated  for  its  duty.  An- 
other advantage,  claimed  for  the  three-cylinder  engine,  is  that 
none  of  the  several  stages  of  the  cycle  in  one  of  the  three  cylinders 
is  precisely  contemporaneous  with  any  other  stage  in  another 
cylinder.  The  effect  of  successive  high-resistance  (compression 


330  SELF-PROPELLED  VEHICLES. 

and  suction),  power-impulse  (expansion)  and  low  resistance 
(exhaust)  are  distributed  or  neutralized ;  thus  rendering  more 
even  the  rotative  stress  on  the  crank-shaft,  and  relieving  the  fly- 
wheel of  a  considerable  percentage  of  its  compensating  duty. 
Whether  or  not  these  explanations  perfectly  explain,  experience 
proves  the  superior  balance  of  the  three-cylinder  engine,  as  used 
by  Duryea  and  several  other  designers. 

MuItiple=Cylinder    Engines. — The    advent    of    the    modern 
high-powered  motor  carriage  involved  the  introduction  of  the 


FiG.228.-The  Duryea  Three-Cylinder  Gasoline  Vehicle  Engine,  with  half  the  crank 
case  sheathing  removed,  snowing  cranks,  crank  shaft,  cam  shaft,  and  working 
parts.  The  three  cylinders  have  common  supply  and  exhaust  tubes;  the  charge 
is  controlled  hy  a  single  throttling  link,  shown  at  the  top,  and  the  igniting  circuit 
haa  three  bridges  for  the  three  cylinders.  Cranks,  as  indicated,  are  at  120  degs. 

multiple-cylinder  engine,  with  four,  and,  latterly,  with  six  cylin- 
ders. The  reason  for  this  change  may  be  found  in  several 
important  considerations : 

1.  The   necessity   of  using  larger,  consequently  heavier,  cy- 
linders to  produce  the  increased  power. 

2,  The   difficulty   of   cooling   large   cylinders  on   high-speed 
engines. 


BALANCING  GASOLINE  ENGINES, 


331 


3.  The   superior  balance  attained  by  increasing  the   number 
of  the  cylinders,  and  rendering  the  power-effect,  as  nearly  as 
possible  constant. 

4.  The  liability  to  vibration  in  a  gas  engine  decreases  as  the 
square  of  the  number  of  cylinders ;  giving  a  four-cylinder  engine 
1 6  times  less  vibration  than  a  one-cylinder,  and  a  six-cylinder,  36 
times  less. 


Fio.229.— A  Typical  Four-cylinder  Engine  (Pierce),  showing  position  of  cranks  and 
working  parts,  including  secondary  shafts. 

The  Four=Cylinder  Engine. — As  shown  on  Faurote's  crank 
and  cycle  diagram,  the  four-cylinder  engine  enables  the  realiza- 
tion of  a  nearly-constant  power  impulse.  In  other  words,  a 
power  stroke  is  occurring  in  some  one  of  the  four  cylinders 
throughout  the  entire  two  revolutions  of  the  cycle.  Since,  how- 
ever the  exhaust  opens  before  the  ends  of  the  power  stroke,  thus 
rapidly  reducing  the  power-pressure  on  the  piston  head,  the  power 
effort  is  neither  constant  nor  uniform.  This  implies  that  the 
balance  of  the  four-cylinder  engine  is  not  perfect,  particularly 


332 


SELF-PROPELLED  VEHICLES. 


at  low  speeds,  when  fluctuations  in  the  power  effect  have  relatively 
greater  opportunty  to  interrupt  the  steady  pull  on  the  shaft.  This 
is  shown  in  a  later  paragraph. 

The  Six-Cylinder  Engine. — Faurote's  diagram  also  shows 
the  six-cylinder  engine  and  its  relative  advantages.  Here,  taking 
the  circle  as  a  complete  cycle  of  two  revolutions,  or  720°,  it  may 
be  seen  that  the  value  of  the  power-efforts  on  the  crank  shaft  is 
practically  constant.  As  indicated  in  the  diagram,  the  order  of 
firing  in  the  cylinders  is  ist,  5th,  3d,  6th,  2d,  4th.  Taking  the 
outermost  of  the  six  concentric  circles  as  representing  the  cycle 
of  the  first  cylinder,  it  may  be  seen  that  the  suction  stroke  begins 
at  the  meridian,  or  i°,  and,  extending  through  180°,  is  followed 
by  the  compression  stroke.  The  firing  stroke  begins  at  360°, 


fii\  2 30. -Crankshaft  of  the  Olds  Six-Cylinder  Engine,  snowing  positions  of  the 

cranks. 

and  is  completed  at  540°.  The  exhaust  opening,  being  set  to 
occur  at  about  500°,  is  slightly  preceded  by  the  maximum  in 
the  fifth  cylinder,  which,  as  may  be  seen,  occurs  at  480°.  The 
maximum  in  the  first  cylinder,  occurring  at  360°,  involves  that 
the  first  third  of  the  power  stroke  in  that  cylinder  is  contem- 
poraneous with  the  last  third  of  the  power  stroke  in  the  fourth 
cylinder.  The  second  third  of  each  power  stroke  is,  therefore, 
the  only  portion  that  is  not  contemporaneous  with  some  part  of 
the  power  stroke  in  some  other  of  the  cylinders.  This  arrange- 
ment achieves  a  fairly  approximate  balance  of  pressure  condi- 
tions, high  with  low,  and  low  with  high,  throughout  the  entire 
rycle  for  six  cylinders. 


BALANCING  GASOLINE  ENGINES.  333 

Multiple-Cylinder  Performance. — A  suggestive  series  of 
experiments  on  the  balance  and  operation  of  four  and  six-cylinder 
engines  is  recorded  in  the  following  quotation  from  the  well- 
known  English  autornobilist,  S.  F.  Edge,  in  a  recent  issue  of 
Motor  Trader.  Beginning  with  a  comparison  of  cylinders  re- 
quired to  produce  a  given  horse-power  efficiency,  say  40  horse- 
power, he  estimates  in  the  following  manner: 

Single  cylinder  diameter,  10  in.;  total  force  of  explosion  on 
piston  head,  28,282  Ibs. 

Double-cylinder  diameter,  about  6  in.;  total  force  of  explosion 
on  piston  head,  14,141  Ibs. 

Triple-cylinder  diameter,  5^  in.;  total  force  of  explosion  on 
piston  head,  9,427  Ibs. 

Four-cylinder  diameter,  about  5  in.;  total  force  of  explosion 
on  piston  head,  7,070  Ibs. 

Six-cylinder  diameter,  4  in. ;  total  force  of  explosion  on  piston 
head,  4,713  Ibs. 

On  the  basis  of  these  figures,  Mr.  Edge  concludes,  as  follows: 

"I  think  at  the  present  time  the  six-cylinder  may  be  taken  as  ideal. 

*  *  *  It  gives  absolutely  smooth  running,  owing  to  the  continuous 
turning  motion,  and,  at  the  same  time,  enormously  reduces  the  cost  of 
up-keep,  owing  to  this  regular  torque,  both  on  tires  and  on  mechanical 
parts. 

"In  order  that  the  steadiness  of  torque  or  turning  effort  in  a  six- 
cylinder  engine  may  be  fully  appreciated,  the  diagrams  given  have  been 
constructed  from  actual  tests. 

"The  first  consideration  to  be  taken  into  account  is,  of  course,  the 
variation  of  pressure  in  the  cylinder.  For  the  purpose  of  discovering 
what  actually  takes  place,  a  standard  40  horse-power  six-cylinder  Napier 
engine  was  put  under  test,  and  a  large  number  of  observations  made  with 
manograph  indicator  and  pressure  recorder.  As  a  mean  of  all  these 
readings,  the  indicator  diagram  [shown  in  Fig.  231]  has  been  constructed. 

"The  vertical  line  is  graduated  to  give  pressures  in  pounds  per  square 
inch.  From  the  figure  it  will  be  noticed  that  the  compression  is  carried 
tc  about  75  Ib.  per  square  inch.  The  ignition  takes  place  considerably 
before  the  end  of  this  stroke,  and  the  pressure  rises  very  rapidly  to  nearly 
450  Ib.  per  square  inch.  The  enormity  of  this  pressure  can  be  better 
appreciated,  when  given  in  total  pressure  on  the  piston.  The  bore  of  the 


334 


SELF-PROPELLED    VEHICLES. 


cylinder  is  4  in.,  the  area  of  the  piston  12.56  square  inches,  and,  therefore, 
the  total  pressure  on  each  piston  is  roughly  2  tons. 

"The  diagram  also  clearly  shows  the  fall  of  pressure  during  the  working 
stroke,  and  the  slight  rise  and  fall  above  and  below  the  atmospheric 
pressure  during  exhaust  and  suction  strokes. 

"At  the  beginning  of  the  suction  stroke,  for  instance,  the  piston  is  being 
pulled  along  at  an  ever-increasing  rate  while  the  crank  travels  through 
approximately  90  degrees.  Then,  until  the  end  of  the  stroke  the  piston 
tends  to  keep  on  moving,  and  has  to  be  retarded  and  brought  to  rest  by 
the  crankshaft.  In  other  words,  the  inertia  of  the  piston  and  parts  moving 
with  it  is  retarding  the  crank  during  the  first  half  of  each  stroke,  and 
urging  it  on  during  the  latter  half. 


PiO.  2 31. -Edge's  Average  Diagram  for  Gasoline  Engine  Performances. 

"The  pressure  in  the  cylinder  and  the  force  necessary  to  accelerate  the 
piston  have  both  been  taken  into  account  in  the  torque  diagram  for  a 
single-cylinder  motor.  The  turning  effort  is  given  in  inch-pounds.  For 
example,  at  point  A,  400  inch-lbs.  represent  a  pressure  of  200  Ibs.  on  the 
crank  pin,  tangential  to  the  crank  arm,  and  acting  at  a  two-inch  radius. 

"The  thick  horizontal  line  represents  the  average  turning-effort  during 
the  four  strokes,  which  constitute  the  cycle.  It  also  shows  the  effort  of 
the  inertia  of  the  piston  in  giving  negative  and  positive  turning  efforts 
at  the  beginning  and  end  of  each  stroke.  At  the  end  of  the  compression 


BALANCING  GASOLINE  ENGINES. 


335 


1 


c 


c 


€ 


XS 


X_ 


1 


One-cylinder. 


Pour-cylinder. 


Six-cylinder. 


33G  SELF-PROPELLED  VEHICLES. 

stroke,  instead  of  getting  a  large  negative  turning  effort,  on  account  ot 
the  increased  pressure  in  the  cylinder,  it  will  be  seen  that  the  torque  has 
only  a  small  negative  value.  This  shows  that  the  inertia  of  the  piston 
coming  to  rest  at  the  top  of  the  stroke  is  nearly  sufficient  to  compress  the 
charge;  also,  when  the  crank  is  on  the  dead  centres,  there  is  no  turning 
effort.  It  is  from  this  diagram  with  its  large  variations  that  we  must 
start  and  endeavor  to  obtain  a  constant  torque. 

"The  dotted  line  in  the  four-cylinder  figure  is  found  by  superimposing 
four  of  these  diagrams,  corresponding  to  four  cylinders  with  crank  at  180 
degrees. 

"It  is  not  fair  to  compare  the  diagrams  for  four  and  six  cylinders,  for, 
the  cylinders  being  all  the  same  size,  the  six-cylinder  engine  will  be  giving 
one  and  a  half  times  the  power  of  the  four,  and  therefore  each  vertical 
height  of  the  dotted  figure  has  been  increased  one  and  a  half  times  to 
the  full  line,  corresponding  to  larger  pistons  to  equalize  the  powers  of 
the  two  engines. 

"The  most  important  point  to  be  noticed  is  that,  with  six  cylinders,  there 
is  always  a  positive  turning  effort  of  at  least  700  inch  Ibs.  on  the  crank 
shaft,  and  that  at  no  point  of  the  cycle  does  it  approach  zero.  With  four 
cylinders  and  cranks  at  180  degrees,  there  must  of  necessity  be  four  points 
in  the  cycle,  viz.,  when  the  cranks  are  on  the  dead  centres,  at  which  there 
can  be  no  turning  effort. 

"The  four-cylinder  diagram  shows  also  four  other  points,  at  which  the 
torque  has  only  a  very  small  positive  value,  namely,  less  than  200  inch  Ib. 
This  is  accounted  for  by  the  retarding  force  of  the  pistons  when  being 
accelerated,  after  the  effect  of  the  explosion  has  passed.  Had  this  diagram 
been  constructed  for  any  other  pistons  than  the  extremely  light  ones  used 
in  the  Napier  engines,  it  is  extremely  probable  that  at  this  point  the  torque 
would  have  a  considerable  negative  value.  The  next  rise  in  the  torque 
is  due  to  the  forward  pressure  of  the  pistons  when  nearing  the  end  of 
the  stroke. 

"A  comparison  of  the  two  diagrams  will  be  far  more  convincing  than 
anything  that  can  be  written  about  them.  The  total  inch-lb.  pressures  are 
given  for  convenience." 

Position  and  Timing  of  the  Valves. — Another  matter  log- 
ically related  to  the  principles  governing  the  balance  of  a  four- 
cycle engine  is  the  proper  timing  of  the  valves.  As  must  be  evi- 
dent on  reflection,  the  valves  must  open  and  close  precisely  at  the 
proper  moment,  otherwise  uneven  working  and  waste  of  power 


BALANCING  GASOLINE  ENGINES. 


33? 


are  inevitable.    The  timing  of  the  valves  ps  well  explained  by  Fay 
L.  Faurote  in  the  following  passage,  quoted  here  by  his  courtesy : 

"The  points  of  opening  and  closing  of  valves  are  designated  in  two  ways : 
either  in  terms  of  degrees  around  the  fly-wheel,  or  as  distance  moved  by 
the  piston  in  the  cylinder.  As  it  is  much  easier,  after  the  motor  has  been 
assembled,  to  determine  the  position  of  the  pis  ion  from  marks  on  the  fly- 


INLET  OPENS. 


INLET  CLOSED. 

VALVE  TIMING  DIAGRAM. 


FIQ.  233.— Faurote'8  Valve-Timing  Diagram,  showing  Timing  of  Valves  for  One- 

Cyliuiler  Engine. 

wheel,  the  former  method  for  setting  valves  has  been  almost  universally 
adopted. 

"As  soon  as  the  engine  is  finished,  two  marks,  diametrically  opposite, 
are  located  on  the  rim  of  the  fly-wheel,  such  that  when  one  is  directly  over 
the  centre  of  the  main  shaft,  the  piston  will  be  at  one  end  of  its  stroke, 
or  in  other  words,  when  either  of  these  marks  is  on  top,  the  piston  will 
be  on  one  of  its  'dead  centres.' 


338 


SELF-PROPELLED  VEHICLES. 


"Referring  to  Fig.  211,  you  will  note  that  when  the  mark,  H,  passes  a 
vertical  line  drawn  through  the  centre  of  the  shaft,  the  piston  has  just 
reached  the  outer  end  of  its  stroke,  and  when  the  mark,  C,  comes  into  this 
position  then  the  opposite  condition  is  true.  These  points,  as  mentioned 
before,  are  respectfully  the  head  and  crank-end  'dead  centres.' 

"Experiments  have  shown  that  the  exhaust  valve  should  open  about 
35  or  40  degrees  before  the  crank  arrives  at  the  'crank-end  dead  centre.' 
Therefore,  No.  3  shows,  approximately,  relative  positions  of  crank  and 
piston  when  this  opening  should  occur.  In  order  to  mark  this  position  a 
line  is  drawn  across  the  fly-wheel  at  the  point,  E.  Next,  as  the  closing 
should  take  place  from  5  to  10  degrees  late,  that  is  after  passing  the  'head- 
end dead  centre,'  the  point,  0,  is  located,  as  represented  in  this  position. 


Fio.  234.-The  Successive  Positions  of  a  Valve-lifting  Cam  (after  Faurate). 

The  inlet,  of  course,  opens  immediately  after  the  exhaust  closes,  so  that 
the  point,  P,  is  next  marked  off  a  short  distance  back  of  O.  Lastly,  the 
time  of  closing  the  inlet  is  determined  (this  varies  from  20  to  50  degrees 
after  crank  has  passed  the  'crank-end  dead  centre')  and  the  point,  I,  is 
settled  upon. 

"Having  located  correctly  all  points  of  opening  and  closing  of  valves, 
we  are  ready  to  proceed  with  the  timing.  Glancing  at  Fig.  234,  you  will 
notice  that  No.  I  shows  the  cam  just  about  to  raise  the  plunger  which 
operates  the  valve;  No.  2  shows  the  valve  at  its  highest  point,  or  maxi- 
mum lift,  and  No.  3,  the  position  of  the  cam  and  roller  at  the  point  of 
closing.  You  will  notice  that  a  small  amount  of  clearance  is  left,  in  order 


BALANCING  GASOLINE  ENGINES.  339 

to  insure  a  proper  seating  of  the  valve,  when  the  cam  has  left  the  roller. 
It  will  easily  be  seen  that  as  soon  as  the  cam  has  turned  far  enough  to  cause 
friction  between  itself  and  the  roller,  the  plunger  will  begin  lifting  the 
valve.  As  long  as  the  roller  turns  freely  it  may  be  assumed  that  the  valve 
is  resting  on  its  seat,  but  as  soon  as  it  appears  to  turn  hard  it  is  taken  for 
granted  that  the  valve  is  beginning  to  open.  Naturally,  when  the  cam  is 
leaving  the  roller,  the  reverse  is  true. 

"Now  let  us  return  to  our  original  proposition,  and  see  what  use  can  be 
made  of  all  this.  We  will  first  turn  the  fly-wheel  over  with  the  starting 
crank  until  the  point,  E,  is  directly  over  the  centre  of  the  crank-shaft. 
According  to  our  calculations,  the  exhaust  valve  should  be  on  the  point 
of  opening.  Place  your  hand  on  the  roller  at  the  bottom  of  the  valve 
plunger,  and  see  whether  or  not  it  turns  freely.  If  you  find  that  it  moves 
easily,  turn  the  engine  a  little  further  in  the  direction  of  the  arrow.  A 
slight  movement  should  cause  the  roller  to  tighten ;  if  it  does  not,  it  shows 
that  the  cam  has  not  yet  come  in  contact  with  it,  and  hence  the  valve  will 
not  open  soon  enough.  In  this  case  turn  the  wheel  back  to  its  former 
position,  and  move  the  cam  back  around  the  cam  shaft  until  the  valve 
begins  to  open  at  the  proper  time.  Frequently,  in  doing  this,  however, 
you  will  find  that  it  will  be  impossible  to  make  the  valve  close  properly, 
and  in  that  case  it  is  necessary  to  braze  a  small  piece  on  the  side  of  the 
cam  to  increase  its  width  in  order  to  hold  the  valve  open  its  required  time. 
Having  adjusted  the  opening,  turn  the  fly-wheel  around  until  the  mark,  O, 
shows  up  on  top,  and  proceed  in  a  similar  way  to  find  whether  or  not  the 
roller  frees  itself  at  the  right  moment. 

"Assuming  that  the  exhaust  valve  has  been  satisfactorily  disposed  of, 
let  us  direct  our  attention  to  the  inlet.  Turn  the  fly-wheel  over  as  before 
until  the  point,  P,  is  just  over  the  shaft.  Then  try  the  roller  to  see  if  it 
is  just  beginning  to  stick.  If  this  is  true,  we  can  go  on;  if  not,  the  same 
method  of  procedure  has  to  be  followed  as  in  the  case  of  the  exhaust 
valve.  When  the  time  for  the  opening  has  been  adjusted  correctly,  revolve 
the  wheel  until  the  mark,  /,  comes  into  position,  when,  of  course,  the  roller 
should  begin  to  loosen.  After  a  little  practice,  by  simply  changing  the 
shape  of  the  cam,  either  by  filing  off  or  adding  to  its  surface,  you  will 
be  able  to  secure  the  results  desired. 

"Each  engine  requires  a  slightly  different  valve-timing,  so  it  is  impossi- 
ble to  give  definite  data  regarding  the  above.  Each  manufacturer  furnishes 
an  instruction  book  which  gives  detailed  information  regarding  proper 
valve-timing  to  be  used  for  any  particular  size  of  motor.  The  diagram 
(Fig.  233)  may  be  made  of  considerable  assistance  by  properly  substituting 
the  values  of  angles  given  in  the  instruction  book." 

In  timing  the  valves  of  a  multiple-cylinder  engine,  this  process 
must,  of  course,  be  repeated  for  each  separate  cylinder. 


CHAPTER    TWENTY-SEVEN. 

GOVERNING  AND  CONTROL,  OP  A  GASOLINE   ENGINE- 

Varieties  of  Controlling  Device. — For  the  governing  of  four- 
cycle engines  several  different  methods  have  been  employed. 
They  are: 

1.  Hit-and-Miss  Governors. 

2.  Throttle  Governors. 

3.  Ignition  Control. 

In  addition  to  these  may  be  mentioned  such  devices  as  the 
Winton  pneumatic  control,  which  may  justly  be  awarded  first 
place  in  its  class. 

.  Theories  of  Governing. — Classifying  governing  apparatus  ac- 
cording to  the  operative  theories  involved,  we  have : 

1.  Valve-lift  regulation. 

2.  Variation  of  the  fuel  mixture. 

3.  Timing  of  the  ignition. 

With  any  one  of^these  means  are  generally  provided  for  both 
automatic  and  intelligent  control  Although,  at  the  present  time, 
many  authorities  contend  that  all  control  of  an  automobile  en- 
gine should  be  solely  in  the  hand  of  the  driver,  automatic  gov- 
ernors still  hold  their  place  on  most  of  the  best-known  makes  of 
engine. 

Hit=and=Miss  Governing. — The  original  Daimler  engines 
were  controlled  by  what  is  known  as  the  "hit-and-miss"  form  of 
governor.  Briefly  described,  the  theory  is  that,  at  excessively 
high  speeds,  the  action  of  the  exhaust  valve  is  interrupted  by  a 
mechanism  which  withdraws  the  cam-actuated  push-rod  out  of 
its  line,  causing  it  to  miss.  At  normal  speeds  the  push-rod  al- 
ways hits  the  end  of  the  valve  stem,  pushing  the  valve  open 
against  the  tension  of  its  spring.  In  the  earlier  models  of  Daim- 
ler's V-shaped  engine  the  opening  of  the  exhaust  valve  was  con- 
trolled by  a  feather  running  in  a  double  eccentric  circular  cam 

340 


GOVERNING  AND  CONTROL. 


341 


groove  on  the  face  of  one  of  the  crank  disks,  as  shown  in  the 
half-sectional  diagram.  By  means  of  a  switch  actuated  by  a 
sliding  sleeve  and  centrifugal  ball  governor,  the  feather  could  be 
shunted  from  its  course,  so  as  to  run  in  a  nearly  circular  path, 
thus  involving  that  the  attached  push-rod  neither  rises  nor  falls, 
and  keeping  the  exhaust  valve  closed.  This  involved  that  the 
burned-out  gases  could  not  escape  from  the  cylinder;  also,  that 


FiO.  235.-One  type  of  Gas  Engine  Governor,  v/hich  Is  an  improved  variation  of  the 
device  used  on  the  early  Daimler  motors.  The  parts  are  as  follows:  A  and  A, 
ball  weights  ;  B  and  B,  bell  cranks  actuating  the  links.  C  and  C,  as  the  balls 
move  outward  resisting  the  tension  of  spring.  S,  and  sliding  sleeve,  D,  on  the 
shaft,  M.  E  is  a  lever  arm  attached  to  L>,  which  moves  the  shaft.  G,  by  contact 
at  F,  as  shown,  thus  throwing  the  pick  blade,  H,  out  of  contact  with  the  end,  J 
of  the  exhaust  valve  rod. 

no  fresh  charge  could  be  taken  in,  the -motor  operation  being  sus- 
pended until  the  speed  should  fall  to  the  proper  rate. 

In  later  models  of  Daimler  engine  a  hit-and-miss  governor  of 
a  different  description  was  used,  its  object  being  to  draw  the 
push-rod  away  from  the  line  in  which  it  could  hit  and  actuate 
the  valve  stem.  As  shown  in  an  accompanying  figure,  the  cam, 
A,  rotated  on  shaft,  L,  bears  upon  the  roller,  C,  and  lifts  the  arm, 
D,  pivoted  at  K,  and  held  in  position  by  a  spring,  L.  By  lifting 
arm,  D,  it  also  lifts  pushrod,  B,  which  opens  the  exhaust  valve 


342 


SELF-PROPELLED   VEHICLES. 


When,  however,  the  speed  of  the  motor  has  increased  beyond  the 
predetermined  limit  a  sleeve  of  varying  diameter,  sliding  on  the 
same  shaft,  L,  is  slid  along,  so  that  the  larger  diameter  is  brought 
to  bear  against  the  downward  extension,  H,  of  the  arm,  F,  thus 
causing  F  to  incline  on  the  pivot,  K,  toward  the  cylinder  (at  the 
right  as  in  the  cut),  hence  pushing  rod,  B,  by  link,  H,  out  of 
range  of  arm,  D,  as  it  is  moved  upward  by  impulse  from  cam, 
A.  In  this  case  the  exhaust  valve  is  not  opened. 


FlG.  236.— Hit  and  Mi«s  Governor  Merhanism  of  the  later  Daimler  Motors. 
FIG. 237.— Mechanism  of  the  Peugeot  Variable  Exhaust  Valve  Lift.  f 

Governing  by  Variable  Valve  Lift. — The  Petigeots  intro- 
duced another  form  of  exhaust  valve  control  apparatus,  which, 
instead  of  operating  to  keep  the  valve  closed,  thus  involving  the 
difficulties  incident  on  retaining  the  exhaust  gases  in  the  cylinder, 
gave  a  varying  lift,  according  to  the  speed  of  the  engine.  As 
shown  in  figure  237,  A  is  a  link  attached  to  spool,  G,  which  is 
slid  on  shaft,  H,  as  the  governor  works  under  speed  of  rotation. 
A  actuates  the  lever,  B,  sliding  the  roller,  J,  on  shaft,  K,  and  thus 
moving  the  fulcrum  of  lever,  D,  varies  the  lift  of  pushrod,  C, 
which  receives  its  motion  from  cam,  H,  bearing  upon  roller,  F. 

Governing  by  Varying  Charge  Volume. — Instead  of  inter- 
rupting the  movement  of  the  exhaust  valve,  several  engineers, 
notably  Winton,  Duryea  and  Mors,  adopted  the  theory  of  govern- 


GOVERNING  AND  CONTROL.  343 

ing  by  controlling  the  intake,  and  thus  varying  the  volume  of  the 
fuel  charge  admitted  to  the  cylinder.  By  this  means  the  opera- 
tion of  the  engine  may  be  maintained  at  any  desired  point  of 
speed  or  power.  As  shown  in  the  diagram  of  the  Mors  engine, 
the  centrifugal  governor  actuates  a  horizontal  valve  shaft,  which, 
in  turn,  throws  levers  controlling  cocks  for  varying  the  fuel 
supply  admitted  to  the  intake  valves.  A  very  similar  arrange- 
ment is  embodied  on  the  Duryea  three-cylinder  engine,  with  the 
notable  exception  that  hand  control  takes  the  place  of  automatic 
governing. 


Winton's  Pneumatic  Governor. — Winton's  governor  controls 
the  volume  of  the  charge  by  varying  the  lift  of  the  inlet  valve. 
It  may  be  operated  both  automatically  and  manually,  and  may  be 
so  adjusted  that  the  engine  can  operate  at  any  desired  rate  of 
speed,  without  interference.  Each  inlet  valve  has  an  elongated 
stem,  which  extends  backward  so  as  to  carry  the  piston  of  a 
small  cylinder  to  the  rear  of  the  valve  chamber.  A  reciprocating 
air  pump  supplies  air  to  this  small  cylinder,  varying  the  travel 
of  its  piston,  according  to  the  speed  of  the  engine.  At  high 
speeds  the  air  pump  works  rapidly,  greatly  compressing  the  air 
before  the  small  piston,  and  consequently  opposing  the  free  open- 
ing of  the  inlet  valve;  at  low  speeds,  it  works  slower,  allowing 
greater  freedom  to  the  inlet  opening.  Of  course,  with  the  pump 
working  direct  from  the  engine  and  constantly  increasing  the  air 
pressure  within  the  small  cylinder,  the  point  would  soon  be 
reached  at  which  the  inlet  valve  could  not  open  and  the  opera- 
tion of  the  engine  must  cease.  To  forestall  this  difficulty,  a  "set 
governor"  or  regulating  cock  is  provided,  for  the  purpose  of  al- 
lowing a  certain  proportion  of  the  air  to  escape  from  the  small 
cylinder,  thus  making  the  rate  of  speed  constant  at  any  desired 
point.  Furthermore,  there  is  another  regulating  vent  cock,  con- 
trolled by  a  push  button  at  the  driver's  foot,  which  enables  him 
to  increase  the  speed  to  the  point  of  allowing  the  air  to  escape  as 
fast  as  it  comes  from  the  pump,  thus  removing  all  obstruction  to 
the  lift  of  the  inlet  valve. 


344 


SELF-PROPELLED  VEHICLES. 


The  details  of  the  Winton  governor  are  given  in  the  accom- 
panying diagram.  Here,  air  compressor  piston,  P,  is  driven  direct- 
ly from  one  of  the  motor  pistons,  and  forces  air  past  the  check 
valve,  V,  into  the  compressed  air  cylinder,  where  it  operates  to 
hold  the  piston  to  the  left,  and  keeps  the  intaking  valve  closed, 
regardless  of  the  piston  suction  tending  to  open  the  valve  by  mov- 
ing it  to  the  right.  By  means  of  the  regulating  cock  the  pressure 
may  be  reduced  in  the  air  cylinder,  thus  permitting  the  intake 
valve  to  open,  more  or  less  as  the  air  pressure  is  more  or  less 


DIAGRAM   OF  WINTON'S  CARBURETTER 
AND  IN  TAKE  VALVE    ACTION. 


AIR  COMPRtSSCR. 


fc'iQ.  238.  -Diagrammatic  Sketch  of  Winton's  Carburetter  and  Intake  Valve  Action, 
as  applied  to  an  Horizontal  Cylinder  Engine. 

reduced  in  the  cylinder.  The  needle  valve,  N,  is  seated  in  and 
carried  by  the  intake  valve  stem,  is  spring  pressed  to  the  left  by 
a  coiled  spring  at  its  right  end,  is  retained  by  a  cross  pin,  S,  and 
co-acts  with  the  adjustable  seat,  A,  S,  to  close  or  open  the  pass- 
age of  gasoline  from  the  float  chamber  to  the  carburetter  under- 
neath, whence  the  mixture  is  drawn  to  the  cylinder  through  the 
intake  valve.  No  gasoline  can  go  to  the  carburetter  unless  the 
motor  piston  is  moved,  and  more  or  less  gasoline  goes  to  the  car- 


GOVERNING  AND  CONTROL. 

buretter  as  the  intake  valve  is  lifted  more  or  less.  The  regulating 
cock  governs  the  action  of  the  motor  by  determining  the  amount 
of  air  that  is  allowed  to  escape  through  the  vent. 

Cadillac  Variable  Valve-Lift. — An  automatic  governing 
device,  which  varies  the  lift  of  the  inlet  and  exhaust  valves  in  a 
manner  analogous  to  that  adopted  by  Winton  is  used  with  the 
Cadillac  four-cylinder  engine. .  In  this  device,  the  pressure  of  a 
liquid  is  used  to  vary  the  liftf  of  the  variable  valve  cams  fixed 
on  a  rotating  countershaft,  as  shown  in  fig.  239.  As  here  shown, 
the  regulation  is  accomplished  by  sliding  the  cam  shaft  endwise. 
The  device  is  described,  as  follows : 

C  is  a  portion  of  the  cam  shaft  showing  two  of  the  cams :  A, 


FIG.  239.-Diagramof  the  Cadillac  Variable-Cam  Oil-Governor  Regulation- 

an  inlet  cam  operating  the  inlet  valve  through  the  roll  and 
valve-lifter,  £;  B,  an  exhaust  cam,  operating  an  exhaust  valve 
through  the  roll  and  valve-lifter  F.  D,  D  are  two  bearings  for 
the  cam-shaft  C,  which  are  also  free  to  move  in  the  bored-out 
parts  of  the  motor  frame.  R  is  a  hardened  steel  finger 

with  its  end  between  the  exhaust  cam,  B,  and  the  inlet  cam,  A. 
R  is  carried  on  the  piston  rod,  J ' ,  which  is  attached  to  the  piston 
head,  H.  The  piston  and  rod,  and  with  them  the  finger,  R,  and 
the  cam  shaft,  C,  are  all  normally  held  in  the  position  shown  by 
the  coil  spring,  G.  With  the  cam  shaft  in  this  position  the  inlet 
cam.  A,  gives  the  maximum  lift  to  the  inlet  valve,  allowing  the 
motor  to  develop  its  full  power  and  speed.  M  is  an  oil  pump 


346 


SELF-PROPELLED  VEHICLES. 


driven  by  the  gear,  N.  The  pump,  M,  draws  its  supply  from  the 
well,  K,  and  discharges  into  the  closed  end  of  the  cylinder,  S. 
This  discharge'  is  governed  by  the  by-pass,  L.  If  L  be  closed 
and  the  motor  started,  the  pump,  M,  discharging  into  the  cylin- 
der, S,  will  force  the  piston,  H,  out  until  it  uncovers  the  edge  of 
the  discharge  port,  T,  and  allowing  the  oil  to  flow  back  into  the 
well,  K.  Under  these  conditions  the  cam  shaft,  C,  is  held  at  the 
other  extreme  of  its  travel  so  that  the  inlet  cam,  A,  causes  a  very 
slight  lift  of  the  inlet  valve,  giving  the  minimum  speed  and 
power  from  the  motor.  If  the  by-pass,  L,  be  partly  open,  the 
tension  of  the  coil  spring,  G,  will  carry  the  cam  shaft  back,  until 


h  o.  2  40.  -Diagram  of  Volume  Throttling  Device  on  the  Mors  Engine.  A  and  A  are 
throttle  valves  on  the  inlet  pipes;  B  and  B,  valve  levers;  C,  valve  shaft,  under 
control  of  the  governor,  D ;  K  and  F,  springs,  used  either  singly  or  together, 
according  to  control  so  as  to  vary  the  opening  of  the  inlet.  System  like  the 
Duryea. 

the  speed  of  the  motor  increases,  so  that  the  discharge  from  the 
pump,  M,  balances  the  tension  of  the  spring,  G,  in  spite  of  the 
opening  of  the  by-pass,  L.  It  will  be  seen  that  under  these 
conditions,  if  the  load  of  the  motor  is  increased  the  reduction  in 
speed  will  immediately  result  in  an  increased  lift  of  the  inlet 
valve,  allowing  the  motor  to  develop  greater  power  to  meet  the 
increased  demand.  If  the  load  on  the  motor  be  decreased,  the  in- 
crease in  speed  will  cause  the  inlet  valve  to  receive  less  lift,  thus 


GOVERNING  AND  CONTROL 


347 


reducing   the  power  of  the   motor  according  to   the    reduced 
demand  upon  it. 

Varying  Mixture  and  Varying  Volume. — Winton  claims,  as 
the  most  conspicuous  advantage  of  his  pneumatic  control,  that 
the  quality  or  air  and  gas  proportions,  of  the  fuel  mixture  are 
constant  at  any  predetermined  point  of  carburetter  regulation, 
and  that  the  volume  only  is  varied,  thus  supplying  fuel  as  re- 
quired and  effecting  a  great  economy.  With  reduced  volume  the 


FIG.  241.— Centrifugal  Governor  of  the  Locomobile  Engine. 
A,  p  nion  on  the  main  shaft;  B,  two-to-ont  gear  on 
pecnn  1  shaft,  carrying  governor  mechanism  j  C,  small 
gear  f  «r  driving  a  dynamo  and  circulating  pump;  D,  D, 
lover -i  pivoted  10  lugs  on  rim  of  B:  E,  E,  governor  balls; 
F.  F,  g')ve:nor  springs;  G,  G,  links  connecting  lever 

arms  to  double  armed  biacket.  1 1,  turning  it  when  the  balls  fly  out  to  positions 
shown  by  dotted  lines;  1 .,  commutator  wheel  of  ignition  circuit-maker;  M,  M, 
lateral  studs  on  bracket,  TI,  N.  groo*  ed  collar  rotated  Ly  studs:  O.  sleeve  on  N, 
having  a  spiral  skit  which  works  on  pin.  P. 

initial  and  compression  pressures  are  also  reduced.  As  against 
"volume  throttling,"  however,  very  many  engineers  still  adhere  to 
the  theory  of  varying  mixture,  reducing  excessive  speeds  by  al- 
lowing greater  proportions  of  air  to  enter  the  mixing  chamber, 
and  increasing  the  proportion  of  gas  as  the  speed  falls.  This 
practice  involves,  of  course,  that  the  same  volume  of  fuel  mixture 


348 


SELF-PROPELLED  VEHICLES. 


is  always  admitted  to  the  cylinder,  and,  consequently,  that  the 
initial  and  compression  pressures  are  invariable.  The  two  theo- 
ries are  one  in  point  of  reducing  the  explosion  pressure,  in  order 
to  reduce  speed. 

The  Riker  Governor. — The  governor  used  on  the  Locomobile 
gasoline  engine,  for  automatically  effecting  the  throttling  of  the 
carburetter  and  the  retarding  of  the  spark,  is  a  good  example  of 
it  class.  As  shown  in  the  accompanying  diagrams,  the  arms  car- 
rying the  governor  weight  actuate  links  at  right  angles  to  their 
normal  position,  and  cause  a  sleeve  on  the  governor  shaft  to  turn 
on  the  shaft  through  part  of  a  revolution,  according  to  the  speed 


Throttle  valve  levers 


FIG.  242.— Diagram  of  the  Governor  and  Control  Connections  of  the  Locomobile 
Engine,  showing  manner  of  automatically  and  manually  throttling  the  car- 
buretter. 

of  the  engine.  The  part  rotation  of  this  sleeve  serves  to  retard 
the  spark  by  shifting  the  contact  of  the  sparking  commutator. 
At  the  same  time,  two  pins,  attached  to  the  sleeve  arms  and  pro- 
jecting through  the  gear  into  the  opposite  direction,  give  a  simi- 
lar turn  to  the  governor  shipper  loosely  let  on  to  the  governor 
shaft.  This  shipper  has  a  hub  with  a  spiral  groove,  through 
which  projects  a  pin  fixed  into  the  shaft,  as  shown.  By  the  part 
revolution  given  the  shipper  by  the  pins  the  hub  moves  back- 
ward along  the  shaft  as  far  as  the  pin  in  the  groove  will  allow  it. 
thus  Actuating  a  link  for  throttling  the  carburetter.  As  the  engine 


GOVERNING  AND  CONTROL. 


slows  down,  the  sleeve  holding  the  commutator  cam  returns  to 
its  position,  and  the  pins,  acting  on  the  shipper,  moves  the  slotted 
hub  into  normal  position,  restoring  the  full  feed  of  fuel  mixture. 
In  starting  the  engine,  the  driver  reverses  the  lead,  retarding  the 
spark  until  the  full  speed  is  attained,  then  leaving  control  to  the 
governor. 

Throttling  the  Fuel  Mixture. — In  practical  operation  the  fuel 
mixture  is  throttled  by  a  valve  operated  directly  by  an  arm 
actuated  by  the  centrifugal  governor.  As  shown  in  the  several 
types  of  carburetter,  described  in  another  chapter,  an  important 


Pro.  243.-  Automatic  Governor  and  Hand  Throttling  Connections  of  the  Toledo 
Engine.  The  parts  are  -.  A ,  the  suction  pipe  of  the  carburetter ;  B,  the  carburetter , 
B',  the  needle  valve  on  the  float  chamber:  C,  the  float  chamber:  D,  throttle  con- 
troller on  rod,  E;  F,  the  governor  lever,  Or,  the  sliding  governor  sleeve:  H, 
governor  weight ;  J.  fibre  gear  on  cam  shaft :  K,  sparking  commutator  ;  L,  cam 
shaft. 

part  in  the  work  of  governing  the  engine  takes  place  in  the  mixing 
chamber.  In  all  devices  for  automatically  regulating  the  air-in- 
take of  the  carburetter,  the  means  adopted  is,  briefly,  some  form 
of  sliding  or  rotating  valve  for  varying  the  opening  of  inlet  tube. 
Accurate  adjustment  of  the  valve  for  the  particular  fuel  to  be 
used  fixes  the  maximum  and  minimum  openings  at  such  points 
that  the  resulting  mixtures  of  air  and  fuel  gas  are  always  within 
the  explodable  limits.  The  result  is  that  a  greater  proportion  of 


350 


SELF-PROPELLED  VEHICLES. 


air  is  admitted  at  a  high  speed,  and,  consequently,  the  power  ef- 
fect of  the  explosion  is  decreased.     As  the  speed  falls,  the  open 
ing  of  the  air  inlet  is  decreased,  and,  consequently,  the  power 
effect  of  the  explosion  is  augmented. 

Varying  the  Point  of  Ignition. — Another  effective  method  of 
controlling  the  speed  of  the  engine,  is  retarding  of  the  spark.  In 
practice,  this  involves  some  means  for  connecting  the  governor 
to  the  rotating  member  of  the  "commutator"  or  contact-breaker, 
so  as  to  produce  the  igniting  spark  at  the  desired  point  in  the 
cycle. 


FiO.  244.— Composite  Indicator  Card  for  a  Gns  Engine,  showing  varying  explosion 
pressures  due  to  varying  the  time  of  the  spark.  A  and  B  are  ahead  C  on  dead 
centre1  D  and  E.  back  of  centre. 

The  Correct  Time  for  Ignition. — As  with  other  matters  con 
nected  with  the  control  of  gasoline  engines,  the  time  of  the  spark 
may  be  varied  only  between  very  definite  limits.  In  general, 
these  limits  are  between  one-third  stroke  ahead  and  one-seventh 
stroke  after  the  dead  centre  of  the  crank,  according  to  the  kind 
of  fuel,  the  strength  of  the  mixture  and  the  normal  speed  of  the 
engine.  If  it  occurs  too  early,  the  point  of  maximum  pressure  is 
reached  before  the  compression  stroke  is  completed,  and  very  fre- 
quently a  "back-kick,"  or  tendency  to  reversal  of  the  motion  fol- 
lows ;  certainly  a  complete  waste  of  the  power  effort  If  it  occurs 


GOVERNING  AND  CONTROL  35] 

too  late,  the  maximum  pressure  is  reached  only  when  the  stroke 
is  far  advanced,  with  the  result  that  a  large  part  of  the  power 
effect  is  lost.  It  is  desirable,  however,  that  the  point  of  maxi- 
mum pressure  should  not  occur  on  the  dead  centre  of  the  crank, 
since  this  produces  a  wholly  unnecessary  jar  and  friction  on  the 
crank  pin,  and,  as  in  the  two  previous  cases,  wastes  the  power. 
Under  usual  conditions,  the  point  of  maximum  pressure,  or  com- 
plete ignition,  should  occur  at  the  beginning  of  the  out-stroke  of 
the  piston. 

Spark=Timing  and  Power  Effect. — The  effects  obtained  by 
varying  the  time  of  ignition  with  a  constant  mixture  are  shown 
by  the  accompanying  diagram  fig.  244. 

Here  points  A,  B,  C,  D,  H,  are  taken  at  the  moment  of  spark 
ignition,  and  the  points,  F,  C,  H,  J ,  K,  at  the  point  of  greatest 
pressure.  The  point,  A,  is  about  one-third  stroke  ahead  of  dead 
centre ;  B,  about  one-fourth  ahead ;  C,  on  the  dead  centre ;  D,  one- 
sixteenth  after ;  £,  one-seventh  after.  The  curves,  AP,  BG,  CH, 
DJ ' ,  EK,  show  graphically  the  relative  power  effort  to  be  ob- 
tained by  varying  the  spark  from  positive  to  negative  lead. 

Spark=ReguIation  and  Speed. — The  field  for  the  most  fre- 
quent application  of  engine  governing  by  spark  regulation  is 
found  in  the  practice  of  shifting  the  point  of  ignition,  so  as  to 
enable  the  maintenance  of  high  speeds.  This  is  true  for  two 
very  definite  reasons : 

1.  With  ordinary  forms  of  jump  and  break  spark,  the  fuel 
ignites  progressively,  instead  of  detonating,  or  exploding,  conse- 
quently entailing  the    lapse  of  an  appreciable  period  before  the 
maximum  pressure  is  reached. 

2.  The  spark  on  a  high-tension  'circuit  always  occurs  at  a  point 
measurably  later  than  the  closure  of  the  primary  circuit. 

At  high  speeds,  therefore,  the  time  of  circuit-closing  is  advanced 
in  proportion  to  the  number  of  revolutions  per  minute,  in  order 
to  begin  the  out-stroke  as  nearly  as  possible  at  maximum  pressure. 
This  is  illustrated  in  the  accompanying  diagram  from  Technics, 


352 


SELF-PROPELLED  VEHICLES 


which  shows  average  points  for  circuit-closure  or  spark-timing: 
for  hand-starting  at  A;  for  slow  running  at  B;  for  full  load  at 
400  R.  P.  M.  at  C;  for  full  load  at  1,200  R.  p.  M.  atD;  for  very 
light  load  at  about  400  R.  P.  M.  at  E.  The  situation  is  set  forth, 
as  follows: 

"Many  attempts  have  been  made  to  render  timing  automatic,  but  up 
to  the  present  none  of  these  has  proved  satisfactory.  To  appreciate  the 
difficulties  involved  it  is  necessary  to  consider  all  the  causes  that  render 
variation  necessary.  It  is  found  that,  as  an  engine  runs  faster,  the  point 
of  sparking  has  to  be  advanced,  so  as  to  cause  it  to  occur  earlier,  and, 
when  an  engine  is  running  very  fast,  it  is  necessary  for  the  theoretica'1 


.FlG.  245.-  Diagram  showing  Proper  Points  for  Closing  the  Ignition  Circuit  at  Various 
Speeds  and  Loads:  A,  point  of  ignition  for  hand  starting ;  B,  point  of  ignition  for 
very  slow  running ;  C,  point  of  ignition  for  full  load  at  about  400  r.p.m.,  D,  point 
of  ignition  for  full  load  at  about  1,300  r.p.m. ;  E,  approximate  point  of  ignition  for 
very  light  load  at  about  400  r.p.m. 

point  of  ignition  to  be  even  as  early  as  no0  of  crank  travel  before  the 
firing  center. 

"The  principal  reason  for  this  is  the  interval  of  time  between  the  first 
ignition  of  the  gas  and  the  instant  when  maximum  pressure  is  reached ; 
this  interval,  being  approximately  constant,  renders  it  necessary  to  advance 
the  point  of  ignition  as  the  engine  speed  increases,  if  it  is  desired  to  keep 
the  point  of  maximum  pressure  at  the  beginning  of  the  working  stroke. 
Two  other  causes  add  to  this  effect — the  lag  of  the  trembler  on  the  induc- 
tion coil,  and  the  lessened  compression  at  high  speeds,  due  to  the  loss  of 
volumetric  efficiency  caused  by  the  wire-drawing  effect  of  both  induction 
and  exhaust  valves.  These  are  slightly  compensated  for  by  the  quicker 
burning  of  the  richer  mixture,  taken  in  at  high  speeds,  caused  by  the  in- 
creased vacuum  in  the  jet  chamber.  It  is  evident  that  the  coil  lag  is  a 
time-element  and  that  the  interval  between  the  completion  of  the  electric 


GOVERNING  AND  CONTROL.  353 

circuit  and  the  "break,"  due  to  the  downward  movement  of  the  trembler, 
will  be  constant  for  the  same  coil,  and  quite  independent  of  the  engine 
speed.  This  factor  is  of  less  importance  since  the  general  adoption  of  high 
speed  tremblers,  and  is,  of  course,  entirely  absent  in  magneto  ignition. 
The  loss  of  volumetric  efficiency  results  in  more  burnt  gas  being  left  in 
the  cylinder  from  the  previous  explosion,  and  the  taking-in  of  a  lessened 
charge,  causing  a  drop  in  the  compression  and  consequent  slower  burning, 
as  the  degree  of  compression  has  considerable  influence  on  the  rate  of 


rtc.  248. — End  view  of  Oakland  engine  showing  balance.  To  the  left  18 
the  driving  mechanism  of  the  valves  and  to  the  right  are  ball-bear- 
ing balance  weights,  A  and  B.  These  weights  are  placed  on  an  ec- 
centric shaft  to  procure  variations  in  setting.  The  construction  is 
such  that  these  weights  are  timed  to  come  into  action  at  the  moment 
When  vibration  sets  in. 

burning  of  an  explosive  mixture  of  given  quality.  The  enriching  of  the 
mixture  at  high  speeds  compensates  for  this  to  a  certain  extent,  depending 
on  the  efficiency  of  the  valve  gear  and  carburetter,  but,  of  course,  this  com- 
pensation is  only  at  the  sacrifice  of  fuel  efficiency. 


354  SHLF-PROPHLlHD   VEHICLES. 

"From  the  foregoing  remarks  it  will  be  evident  that  if  the  mixture 
is  throttled,  thus  lowering  the  compression,  it  will  be  necessary  to  advance 
the  spark  to  obtain  a  correct  diagram  at  the  same  engine  speed;  and  this 
effect  will  generally  be  intensified,  as  throttling  usually  results  in  a  weak- 
ened mixture.  Any  automatic  device  must,  therefore,  not  only  vary  the  con- 
tact to  compensate  for  variation  of  engine  speed,  but,  if  correct  ignition 
and  maximum  efficiency  is  desired,  also  for  varying  degrees  of  throttling 
and  alterations  of  quality  of  mixture." 

Spark  and  Throttle  Governors. — As  may  be  readily  under- 
stood, governing  by  retarding  the  spark  is  very  wasteful  of 
energy,  since  it  results  inevitably  in  exhausting  before  ignition 
is  complete.  For  this  reason,  when  spark  regulation  is  used  in 
automatic  governing,  it  is  generally  in  connection  with  mixture- 
throttling,  which  doubly  reduces  the  power  effect.  In  general, 
however,  precisely  the  same  result  follows  with  the  use  of  a  weak 
mixture  as  with  the  use  of  a  retarded  spark — reduced  power  effect 
and  slow  combustion  of  the  charge.  A  rich  mixture  and  a  posi- 
tive lead  to  the  spark  alike  produce  increased  power  effect  and 
rapid  combustion.  The  diagram,  shown  in  Fig.  222,  could  be 
produced  as  the  result  of  varying  the  fuel  mixture,  as  readily  as 
by  shifting  the  time  of  the  spark-occurrence. 

The  diagram  in  Fig.  245  shows  that  the  best  effect  of  the  ex- 
ploding fuel  may  be  obtained  only  by  .advancing  the  spark  when 
desiring  to  run  at  high  speeds.  In  order  to  achieve  this  end,  sev- 
eral cars,  notably  the  Jeffrey  Rambler,  are  equipped  with  an  au- 
tomatic spark-advance  governor. 


CHAPTER  TWENTY-SEVEN. 

CLUTCHES  AND  TRANSMISSIONS. 

Essentials  of  a  Gasoline  Vehicle. — Every  vehicle  propelled 
by  a  hydro-carbon,  or  internal-combustion,  engine,  popularly 
known  as  a  "gasoline  engine,"  must  have  a  transmission  gear,  for 
varying  the  ratio  of  speed  and  power  transmitted  to  the  road 
wheels.  The  transmission  gear  is  connected  to  the  engine 
shaft  through  a  clutch,  which  may  be  thrown  into  engagement, 
to  start  the  vehicle,  and  thrown  out  again  to  stop  it. 

It  is  necessary  to  use  some  form  of  throw-out  clutch,  because 
it  would  be  difficult  to  start  the  engine  with  the  machinery  and 
running  gear  connected. 

It  is  desirable  to  use  a  speed-reducing  and  changing  trans- 
mission, between  the  engine  and  the  road  wheels,  because  the 
internal-combustion  engine  is  less  flexible  than  the  steam  engine, 
and  requires  a  reducing  gear  to  effect  a  rational  economy.  With- 
out such  a  gear,  the  road  wheels  may  be  driven  direct  from  the 
engine  shaft,  and  changes  of  speed  and  power-effect  produced 
by  throttling,' as  already  explained.  The  fact  remains,  however, 
that  a  much  more  powerful  engine  would  be  required  than  is  now 
used  on  any  vehicle.  This  is  true  because,  with  every  throttling 
of  the  charge  of  a  gas  engine,  the  initial  pressures  are  reduced, 
with  a  consequent  reduction  of  the  explosion  and  the  mean  effec- 
tive pressures.  In  order,  therefore,  to  run  at  moderate  speeds, 
the  engine  would  have  to  be  throttled  down  to  one-half  or  one- 
third  its  normal  power.  In  ascending  hills  full  power  would  often 
be  required,  and  this  would  be  far  in  excess  of  what  is  generally 
used. 

The  force  of  these  remarks  becomes  apparent  when  we  re- 
member that  the  best  efficiency  of  a  gas  engine  is  obtained  by 
maintaining  as  nearly  as  possible  a  constant  speed  and  power 
output. 

SET 
uv 


356 


SHIP -PRO  FELLED  VEHICLES. 


The  French  designer,  Vallee,  drove  his  vehicles  from  the  en- 
gine shaft  through  leather  belting.  Duryea  uses  a  two-speed 
transmission,  doing  all  his  driving,  except  hill-climbing,  on  the 
high  gear,  and  varying  the  speed  by  throttling.  Both  use  very 
high-powered  engines,  in  order  to  allow  a  wide  range  of  throt- 
tling, from  maximum  to  minimum  power  without  danger  of 
failure. 


FIG.  247.  FIG.  248. 

FIG.  247^-Internal  Cone  Clutch  of  the  Peerless  Car.  A,  engine  fly-wheel  •.  B,  female 
cone;  C,  male  cone;  D,  universal  coupling  on  male  cone;  E,  bushing  on  D;  F, 
collar  keyed  on  D;  G,  key,  H,  ball  bearings  for  taking  up  the  thrust  on  dis- 
engaging clutch ;  J,  flange  on  ball  cone  ;  K,  receptacle  on  D  lor  operating  yoke ; 
L,  spiral  spring  for  retaining  clutcli  surface  contact;  M,  leather  band  riveted  on 
C,  giving  good  friction  surface;  Q,  main  shaft;  R,  portion  of  shaft  turned  down 
to  fit  fly-wheel ;  S,  portion  of  shaft  turned  down  to  receive  clutch  sleeve ;  Z,  flange 
to  which  fly-wheel  is  bolted. 

FlG.  248,-External  Cone  Clutch  of  the  Pope-Toledo  Car.  A.  fly-wheel  clutch  cone; 
B,  fly-wheel;  C,  fly-wheel  clutch  stud  plate;  D,  D,  clutch  spring  studs;  E.  clutch 
spring;  F,  spring  retainer;  G,  retainer  lock  nut;  H,  sliding  sleeve  for  setting 
clutch;  J,  crank  shaft  end;  K,  crank  shaft  nut;  L,  tail  shaft;  M,  ball  thrust 
collar ;  N,  ball  thrust  bush ;  O,  sliding  sleeve  bush  ;  P,  clutch  cone  leather. 

Forms  of  Clutch. — There  are  four  forms  of  clutch  in  use  on 
gasoline  propelled  vehicles : 

1.  Cone  Clutches. 

2.  Drum  and  Band  Clutches. 

3.  Expanding  Ring  Clutches. 

4.  Compression  .Disc  Clutches. 


CLUTCHES  AND   TRANSMISSIONS. 


35? 


Requirements  in  Clutches. — The  leading  requirements  in  a 
serviceable  clutch  are : 

1.  Gradual  engagement,  in  order  to  avoid  jerks  due  to  too 
sudden  throwing  on  of  the  power. 

2.  Large  contact  surfaces. 

Forms  of  Transmission  Gear. — There  are  four  forms  of 
transmission  gear  in  use  at  the  present  time : 

i.  Sliding-Spur,  or  Clash-Gear  Transmissions,  which  may  be 
distinguished  in  two  forms : 


FIG.  249.-End  View  and  Cross  Section  of  the  Packard  Expanding  Ring  Clutch. 

a.  One-lever,   sliding-sleeve    gears,    such    as    the    Panhard- 
Levassor,  Decauville,  Riker,  Packard  and  Toledo. 

b.  One-lever,  selective-finger  or  gridiron  slot  transmissions, 
such  as  the  Daimler,  Columbia,  Knox,  and  numerous  other 
forms  used  on  modern  gasoline  cars. 

2.  Meshing-Spur,   or   Individual—Clutch   Transmissions. 
Prominent  among  these  may  be  mentioned  the  old  Winton 

and  Haynes-Apperson  gears. 

3.  Planetary    Transmissions. 

Among    planetary    transmissions    may   be    mentioned    the 
Puryea,  Qlds  and  Cadillac. 


358  SELF-PROPELLED     VEHICLES. 

4.  Friction-Disc  Transmissions. 

In  addition  to  these  may  be  mentioned  the  belt  and  pulley 
transmission  of  the  early  Daimler  vehicles  and  others. 

Cone  Clutches. — The  cone  clutch  is  the  typical  form,  and 
was  formerly  in  practically  universal  use.  As  shown  in  ac- 
companying figures,  cone  clutches  consist  of  two  members:  a 
dish-shaped  ring,  secured  to  the  face  of  the  fly-wheel,  and  a 
truncated  cone,  carried  by  a  sleeve  sliding  on  the  main  shaft, 
and  held  in  close  fit  by  means  of  a  spring.  The  first  member 
is  called  the  "female  cone,"  the  second,  the  "male  cone." 


Fio.  250.— Mechanism  of  the  Expanding  Ring  Clutch  of  the  Columbia  Light  Car. 

There  are  two  varieties  of  cone  clutch:  the  external  cone 
clutch,  in  which  the  male  cone  is  forced  against  the  fly-wheel 
from  the  rear;  and  the  internal  cone  clutch,  in  which  the  male 
cone  is  contained  within  the  other  member  and  is  forced  into 
contact  from  the  front.  The  latter,  or  self-contained  clutch, 
is  a  generally  favored  pattern.  In  both  forms  of  cone  clutch 
the  contact  is  between  a  metal  surface  and  one  of  leather  or 
fibre.  Because  it  is  essential  that  no  oil  or  grit  be  allowed  to 
collect  on  the  friction  surfaces,  the  internal  cone  clutch  is  pre- 
ferable, as  enabling  the  surfaces  to  be  more  readily  protected. 

,  • 

Cone  Clutch  Efficiency. — In  order  to  achieve  good  power 
transmission  by  means  of  a  clutch,  two  things  are  essential; 


CLUTCHES  AND   TRANSMISSIONS. 


35H 


1.  Sufficient  friction  surface. 

2.  Proper  angularity  of  the  cone. 

The  angularity  generally  adopted  is  between  12°  and  15°,  gen- 
erally nearer  the  latter,  which  affords  a  friction  surface  of 
about  J/s  the  fly-wheel  diameter  in  breadth.  To  increase  or 
decrease  the  angle  of  the  cone  would  neutralize  the  friction 
effect. 


FIG.  251.-MultipleDisc  Clutch,  sectioned  to  show  construction. 

Troubles  with  Cone  Clutches. — Although  cone  clutches  pos- 
sess the  advantage  of  simple  construction,  and  may  be  readily 
thrown  in  and  out  of  action,  they  are  subject  to  two  grave 
defects : 

1.  Unless  skillfully  handled,  the  power  will  be  thrown  on 
with  a  jerk,  not  gradually,  as  it  should  be,  thus  jarring  the 
machinery  and  annoying  the  passengers. 

2.  The  friction  surfaces,  when  worn,  are  liable  to  slip  on 
each  other,  thus  losing  power  and  jerking  rather  than  pulling 
the  machinery. 


360 


SELF-PROPELLED   VEHICLES. 


CLUTCHES  AND   TRANSMISSIONS.  361 

In  order  to  avoid  the  first  difficulty  several  designers  have 
placed  small  spiral  springs  at  intervals  on  the  surface  of  the 
male  cone,  or  between  the  cones,  thus  rendering  the  grip  be- 
tween the  surfaces  gradual.  Such  springs  may  act  efficiently, 
but  are  objectionable  as  complicating  construction. 

Drum  and  Band  Clutches. — Clutches  of  the  drum  and  band 
type  are  really  only  variations  of  the  form  of  brakes  most 
common  on  motor  carriages.  They  are  generally  used  in  con- 
nection with  planetary,  or  epicyclic,  transmissions,  and  consist 
simply  in  leather  or  fibre  rings,  which  are  compressed  against 
the  periphery  of  drums,  in  order  to  prevent  rotation.  They 
will  be  described  in  connection  with  planetary  transmissions. 

Expanding  Ring  Clutches. — Expanding  ring  clutches  are 
used  by  several  designers  as  convenient  substitutes  for  the 
ordinary  cone  clutches.  Mechanically,  they  are  identical  with 
the  expanding  ring  brakes,  except  for  the  fact  that  their  use 
accomplishes  the  connection  into  a  working  unit  of  two  rotat- 
ing shafts.  According  to  engineering  authorities,  the  cone 
clutch  and  the  expanding  band  clutch  are  similar  in  theory,  the 
angularity  of  the  cone  in  the  cone  clutch  being  the  same  as 
the  angle  of  the  operating  levers  in  the  band  clutch.  The 
friction  surfaces  of  the  ring  clutch  may  be  both  of  metal  or 
the  ring  may  be  faced  with  fibre. 

Compression  Disc  Clutches. — The  disc  clutch  is  the  latest 
and  most  satisfactory  solution  of  the  clutch  problem.  Briefly 
described,  it  consists  of  three  or  more  metal  discs  secured  al- 
ternately to  the  clutch  shaft  and  to  the  face  of  the  engine 
fly-wheel.  By  the  pressure  of  a  powerful  spring  the  discs  are 
forced  together,  thus  involving  a  close  driving  contact,  which 
cannot  slip.  Unlike  other  forms  of  clutch,  the  disc  clutch 
should  be  soaked  with  oil.  This  contact  is  gradually  made, 
as  is  not  the  case  with  all  other  clutches. 

Friction=Disc  Transmissions. — The  friction-disc  transmis- 
sion undoubtedly  has  a  large  future.  It  obviates  all  the  dim"- 


362  SBLF-PROP&UMD    VEHICLES. 

culties  incident  upon  the  use  of  sliding  spur  gears  or  planetary 
speed  changers,  and  also  does  away  with  clutches  of  all  descrip- 
tions. In  practical  service  upon  all  weights  of  vehicle  it  has 
already  demonstrated  its  ability  to  transmit  power  as  efficiently 
as  any  other  device.  Briefly  described,  the  friction  transmis- 
sion consists  of  two  elements,  the  driving  friction  disc  and  the 
driven  friction  disc.  The  simplest  form,  the  driven  disc  is 
set  on  a  shaft  at  right  angles  to  the  driving  disc,  and  is 


TTG.  253  —A  Type  of  Friction  Transmission.  A  is  the  driven  disc  on  the  transmission 
shaft;  H,  Baud  C  are  friction  idlers  driven  from  driving  disc,  D;  E,  is  the  clutch; 
F,  the  transmission  frame;  G,  the  lever  for  changing  the  speeds  by  shifting  disc 
A,  along  shaft,  H. 

rotated  by  friction  contact  between  its  edge  and  the  face  of  the 
driver.  When  the  edge  of  the  driven  disc  is  driven  on  a  circle 
nearest  the  periphery  of  the  driver,  its  speed  is  greatest.  As 
it  is  slid  along  its  shaft,  toward  the  centre  of  the  driver,  as 
may  be  done  by  means  of  a  squared  portion  or  splines,  its 
speed  is  constantly  decreased.  At  the  center  of  the  driving 
disc  it  ceases  to  rotate.  If  slid  beyond  the  centre  of  the  driver, 
its  motion  is  reversed. 


CLUTCHES    AND    TRANSMISSIONS. 


363 


Clutch  Requirements. — The  construction  of  a  clutch  must  be 
such  that  it  does  not  apply  the  full  power  of  the  engine  at  once, 
but  does  so  gradually,  in  order  that  the  car  may  start  slowly  and 
without  jerking.  If  the  power  were  applied  suddenly,  the  ma- 
chinery might  be  badly  strained,  or  again,  the  resistance  of  the 
stationary  car  might  be  sufficient  to  overcome  the  momentum  of 
the  engine  and  cause  it  to  stop  between  power  strokes. 


FIG.  254.— Type  of  cone  clutch  used  on  the  Marmon 
car.  The  clutch  is  faced  with  thermoid.  Eight 
spring  pressed  plungi-s  under  the  facing  secure 
easy  engagement.  A  g-oove  is  turned  iu  the  fly- 
wheel rim  and  provided  with  an  outlet  to  prevent 
any  surplus  oil  from  getting  on  the  clntch  face 
and  a  snort  shaft  with  two  joints  connects  the 
clutch  with  the  propeller  shaft. 


A  clutch  is  not  necessary  on  automobiles  propelled  by  steam 
or  electricity  as  these  powers  are  more  flexible,  that  is,  the  ap- 
plication of  power  is  not  intermittent,  as  with  the  gas  engine. 

A  clutch  must  be  capable  of  transmitting  the  maximum  power  of  the 
engine  to  which  it  is  applied  without  slip  or  loss.  This  is  in  order  to 
avoid  a  waste  of  power.  In  addition  a  clutch  must  be  easy  to  operate, 
being  engaged  or  disengaged  with  minimum  exertion  on  the  part  of  the 
operator. 


364 


SELF-PROPELLED    VEHICLES. 


CLUTCHES  AND   TRANSMISSIONS.  365 

It  is  essential  that  the  clutch  disengage  promptly,  that  there  may  be 
no  drag  or  continued  rotation  of  the  parts  after  disengagement.  It  must 
be  of  such  design  that  the  co-acting  surfaces  will  operate  for  extended 
periods  without  material  wear.  Silent  operation  whether  in  engaging  or 
releasing,  is  a  desirable  quality. 

A  clutch  should  be  easy  of  removal  for  inspection  or  repairs  and  should 
be  provided  with  suitable  adjustments  so  that  a  certain  amount  of  wear 
between  the  surfaces  could  be  compensated  for  without  renewal  of  sur- 
facing. 

It  should  be  as  simple  as  possible,  of  substantial  design  and  construction, 
and  with  as  few  operating  parts,  which  would  be  liable  to  get  out  of  order, 
as  is  consistent  to  preserve  proper  operation.  In  event  of  the  parts  need- 
ing replacement,  or  of  wear  being  serious  enough  to  require  new  frictional 
surfaces,  it  should  be  of  such  construction  that  the  replacements  could  be 
made  with  minimum  expense. 

The  Gearless  Transmission. — The  transmission  of  the  large 
Gearless  cars,  which  is  their  distinguishing  feature,  is  of  the 
planetary  type  as  shown  in  fig.  255. 

There  are  two  speeds  forward  and  reverse  without  the  use  of  any  gears, 
the  high  speed  being  direct,  in  which  the  change  speed  elements  revolve 
together  as  a  unit,  with  no  internal  friction  nor  rolling  contact,  the  entire 
change  speed  unit  revolving  together  as  a  flywheel.  It  consists  of  six 
large  special  fiber  rolls  of  conical  shape  revolving  on  and  in  an  exterior  and 
interior  cone.  These  two  cones  co-act  with  a  sliding,  double  faced,  solid 
jaw  clutch,  which  is  moved  to  the  extreme  forward  position  to  give  the  low 
speed  forward,  and  to  the  extreme  rearward  position  to  give  the  reverse. 
The  internal  cone  is  constantly  pressed  toward  the  external  cone  by  means 
of  a  spring,  so  as  to  always  insure  "bite"  enough  to  make  the  six  cone 
rollers  revolve  without  slipping  in  the  low  speed  and  reverse  drives. 

The  gearless  transmission  has  the  advantage  of  no  change  gear  friction 
whatever  on  the  high  speed,  or  direct  drive,  and  rolling  friction  engage- 
ment in  the  low  speed  and  reverse. 

The  coned  rollers  are  held  laterally  in  a  cage  of  large  diameter  and  press 
against  an  iron  cone  made  fast  to  the  extension  of  the  motor  shaft.  On 
their  opposite  faces  they  press  against  an  internally  faced  cone,  also  of 
iron,  and  which  is  concentric  with  the  propeller  shaft  of  the  car.  The  cone, 
roller  and  cup  angles  are  such  that  the  three  elements  roll  together  with- 
out any  sliding,  and  hence  without  sliding  friction,  save  in  case  of  the 
slipping  of  the  six  rollers.  To  avoid  the  slipping  of  the  rollers  on  the  cone 
or  in  the  cup  a  heavy  spring  pressure  is  applied  to  the  cone  cup  to  force 
it  towards  the  driving  cone,  this  pressure  being  sufficient  to  make  it  im- 
possible for  the  motor  to  slide  the  roller  surfaces  on  the  cone  or  in  the  cup. 

Cork  Inserts. — In  connection  with  clutches,  cork  is  used  to  a 
considerable  extent  and  with  success.  It  is  a  peculiar  product 
and  performs  in  accordance  with  its  peculiar  characteristics.  In 
the  first  instance,  it  has  a  high  co-efficient  of  friction,  so  that  high 
pressure  is  not  necessary,  and  its  co-efficient  of  friction  is  but 


366 


SELF-PROPELLED   VEHICLES. 


little  influenced  by  the  question  of  lubrication.  In  other  words, 
the  cork  will  hold  on  a  dry  surface  or  if  the  surface  be  lubricated 
and  the  degree  of  polish  of  the  surface  be  not  a  factor  of  such 
marked  import  as  would  be  the  case  in  the  absence  of  the  cork. 

High  temperatures  are  not  so  liable  to  char  cork  as  they  would  leather 
or  fibre.  This  is  an  important  matter  in  clutches.  Even  wood  will  be 
charred  by  the  heat  generated  in  clutches  under  certain  conditions,  which 
is  fair  evidence  of  the  fact  that  the  temperature  can  raise  to  a  point  as 
high  as  500  degrees  centigrade. 


!  i 


PIG.  256. — Showing  method  of  mounting  a  cone  clutch.  The  dotted  out- 
line of  clutch.  The  dotted  outline  of  clutch  pedal  shows  position 
for  releasing  the  clutch. 

As  a  rule,  the  corks  are  forced  into  suitable  cavities  formed  for  them  in 
one  of  the  metallic  frictional  surfaces.  The  corks  are  previously  boiled 
and  thereby  softened  and  then  pressed  into  the  cavities.  Thus  established 
in  a  metal  surface,  they  normally  protrude  above  the  surrounding  surface 
and  engage  first  when  the  surfaces  are  brought  together.  If  sufficient  pres- 
sure be  applied  to  the  clutch  they  are  forced  down  flush  with  the  metal 
surface  and  act  with  it  in  carrying  the  load.  Following  the  release  of  the 
load,  they  again  protrude  beyond  the  surrounding  metal  surface. 

Two  forms  of  cork  are  used,  one  being  the  cork  in  its  natural  condition, 
the  other  prepared  as  follows :  Small  pieces  are  compressed  into  sheets 
and  blocks  of  any  desired  shape  under  very  great  pressure  and  under 
enough  heat  to  cause  the  natural  gums  of  the  corks  to  exude  and  act  as  a 
binder. 


CHAPTER  TWENTY-NINE. 

TRANSMISSIONS. 

Principles  of  Operation. — The  term  transmission  has  come 
to  mean  only  that  portion  of  the  transmission  gearing  proper 
which  lies  between  the  engine  shaft  and  the  propeller  shaft  or 
driving  chain,  and  does  not  include  the  rest  of  the  driving  gear 
such  as  the  bevel  gear,  jack  shaft  or  differential. 

A  transmission  is  necessary  on  account  of  the  nature  of  the 
gas  engine  cycle.  The  piston  of  a  gas  engine  is  operated  by  an 
intermittent  force,  and  not,  as  in  the  case  of  a  steam  engine,  by  a 
continuous  pressure.  A  gas  engine  running  at  high  speed,  how- 
ever, produces  a  fairly  uniform  turning  effect,  so  that  after  it 
gets  under  way  the  intermittent  action  of  the  driving  force  is 
not  so  noticeable. 

A  four  cycle  engine  which  receives  only  one  impulse  in  two  re- 
volutions, must  give  to  the  flywheel  during  that  impulse,  enough 
momentum  to  keep  the  engine  going  at  approximately  uniform 
speed  during  the  exhaust,  suction  and  compression  strokes. 

In  other  words,  the  flywheel  must  overcome  by  its  momentum,  for  one 
and  a  half  revolutions,  the  resistance  of  the  load  and  also  that  due  to  the 
back  pressure  of  exhaust,  suction  and  compression. 

So  far  as  turning  effect  is  concerned,  that  is,  the  number  of 
impulses  per  revolution,  one  steam  engine  cylinder  is  equivalent 
to  four  gas  engine  cylinders  of  the  four  cycle  type,  therefore, 
with  the  latter  a  heavy  flywheel  is  necessary  to  transform  the 
highly  varying  and  intermittent  driving  force  into  one  of  nearer 
constant  intensity  so  that  uniform  rotation  may  be  approached. 

One  of  the  first  objects,  therefore,  of  a  transmission  is  to 
allow  the  engine  to  speed  up  until  the  energy  which  it  stores  up 
in  the  fly  wheel  is  sufficient  to  keep  the  shaft  revolving  at  a  speed 
showing  no  great  percentage  of  variation. 

Secondly,  a  transmission  is  necessary  when  the  engine  is  re- 
quired to  work  under  a  heavy  load  which  under  other  circum- 

867 


368 


SELF-PROPELLED    VEHICLES. 


stances  would  cause  it  to  slow  down,  and  stall  if  required  to 
work  under  such  conditions  any  great  length  of  time. 

For  instance,  it  may  be  assumed,  I,  that  a  man  is  raising  a  bucket  in  a 
well  by  winding  a  rope  around  the  drum  of  a  windlass  as  shown  in  fig. 
257,  and  2,  that  the  bucket  must  be  raised  a  certain  number  of  feet  every 
minute;  then  if  the  bucket  of  water  weigh  such  an  amount  as  to  require 
all  his  strength  to  fulfill  these  conditions,  and  that  any  extra  weight  added 
to  the  bucket  would  over  tax  Jiis  strength  to  such  an  extent  as  to  make 
further  progress  impossible,  it  is  evident  that  some  mechanical  contrivance 
is  necessary  which  will  enable  him  to  exert  the  same  strength  but  apply  it 
through  a  longer  period  of  time. 

To  make  this  plain,  it  may  be  assumed  that  he  wished  to  lift  a  barrel 
weighing  600  pounds,  ten  feet.  This  would  be  impossible  for  him  to  ac- 
complish in  a  direct  manner.  If,  however,  he  should  build  an  incline 
long  enough,  he  would  be  able  to  roll  it  up  accomplishing  the  same  work, 
but  taking  a  longer  time.  Another  way  of  doing  this  would  be  by  the 
use  of  a  lever. 


FIGS.  257  and  258. — Diagrams  Illustrating  transmission  principles.  A 
lever  is  shown  in  fig.  257  attached  direct  to  a  drum  and  in  fig1.  258 
gear  wheels  are  shown  placed  between  the  lever  and  drum.  If  the 
force  applied  to  the  lever  be  the  same  in  each  case,  a  heavier  weight 
may  be  raised  with  the  geared  lever  because  the  force  acts  through  a 
greater  distance,  the  gear  wheels  multiplying  the  revolutions  of  the 
lever  necessary  to  lift  the  weight  a  given  distance. 

Now,  returning  to  the  first  illustration,  instead  of  turning  the  drum  of 
the  windlass  direct  by  hand,  a  gear  may  be  placed  on  the  end  of  the  drum 
and  constructed  to  mesh  with  a  smaller  gear  attached  to  the  lever  as  shown 
in  fig.  258. 

To  illustrate  the  principles  involved,  it  may  be  assumed  that  the  large 
gear  on  the  drum  is  three  times  the  diameter  of  the  small  gear.  It  will, 
therefore,  require  three  revolutions  of  the  small  gear  to  one  of  the  large 
gear,  and  the  pressure  exerted  will  be  only  one-third  of  that  required 
if  the  crank  were  fastened  to  the  drum  direct  as  shown  in  fig.  257.  In 
either  case,  the  work  done  is  the  same. 

To  compare  this  with  the  conditions  of  automobile  operation,  the  work 


TRANSMISSIONS. 


369 


required  to  lift  the  bucket  may  be  represented  by  the  work  required  to 
drive  the  machine,  and  the  man's  effort,  or  force  applied  to  the  lever  of 
the  windlass,  by  the  pressure  exerted  on  the  piston  of  the  engine. 

Work  is  the  product  of  two  factors:  force  and  distance 
through  which  the  force  acts. 

The  office  of  the  transmission  is  to  keep  this  first  factor — force 
• — within  proper  limits  at  the  engine  while  allowing  it  to  vary 
widely  at  the  rear  driving  wheels  of  the  car. 

To  illustrate  this  in  the  operation  of  an  automobile,  a  conventional  dia- 
gram fig.  259,  shows  an  engine  shaft  placed  parallel  to  the  rear  axle. 
Two  cone  pulleys,  one  on  the  engine  shaft  and  one  on  the  rear  axle  are 
connected  by  a  belt  so  that  the  speed  of  the  engine  may  be  varied  by  shift- 
ing the  belt  from  one  side  to  the  other;  that  is,  if  the  belt  be  started  on 
the  left  side  of  the  pulleys  where  the  diameter  A  is  one-third  the  diameter 


-  [pj 


FIG.  259. — Conventional  diagram  illustrating1  transmission  principles  as 
applied  to  the  automobile.  A  belt  connects  two  cone  pulleys,  one 
on  the  engine  shaft  and  one  on  the  rear  axle.  By  shifting  the  belt 
to  the  right  or  left,  the  speed  of  the  engine  is  respectively  diminished 
or  increased  in  relation  to  the  speed  of  the  rear  axle. 

B,  the  engine  will  revolve  three  times  for  each  revolution  of  the  rear  axle. 
Similarly  when  the  belt  is  in  position  2,  where  diameter  C  is  equal  to 
diameter  D,  then  the  engine  will  revolve  at  the  same  rate  as  the  rear 
axle.  Position  3,  where  diameter  E  is  three  times  diameter  F,  the  engine 
will  revolve  at  only  one-third  the  rate  of  the  rear  axle. 

Position  2  corresponds  to  the  example  of  the  man  raising  a  bucket 
with  the  crank  fastened  direct  to  the  windlass  hub  (fig.  257),  while  posi- 
tion i,  corresponds  to  raising  a  bucket  with  the  geared  lever  (fig.  258). 
The  cone  and  belt  transmission  allows  the  speed  of  the  engine  to  be  varied 
considerably  for  a  given  speed  of  the  rear  wheels. 

Now,  for  a  given  amount  of  work,  the  two  factors  force  and  distance 
are  inversely  proportional,  that  is,  if  the  distance  be  increased,  the  force 
will  be  diminished  a  corresponding  amount. 


370  SELF-PROPELLED   VEHICLES. 

In  the  application  of  this  to  the  automobile,  the  factor  distance, 
is  represented  by  the  distance  traveled  by  the  engine  piston  dur- 
ing the  power  strokes,  and  force,  by  the  pressure  exerted  on  the 
piston  during  these  strokes. 

Since  the  two  factors  are  inversely  proportional,  the  factor  force  may 
be  kept  within  an  allowable  limit  when  a  heavy  load  is  put  on  the  rear 
axle  by  shifting  the  belt  of  the  transmission  to  the  left  so  that  the  speed 
of  the  engine  is  increased  in  relation  to  the  speed  of  the  rear  axle,  thus 
increasing  the  factor  distance,  and  diminishing  the  factor  force. 

In  other  words,  when  a  heavy  load  is  put  on  the  rear  axle,  the 
speed  of  the  engine  may  be  increased  in  relation  to  the  speed  of 
the  rear  axle,  by  shifting  the  belt  to  the  left.  This  operation,  I, 
reduces  the  resistance  to  be  overcome  by  the  piston,  and  2,  stores 
up  more  energy  in  the  fly  wheel  both  of  which  tend  to  keep 
the  engine  moving  during  the  three  non-power  strokes  of  the 
cycle. 

In  the  early  development  of  the  automobile,  a  belt  transmission  some- 
what similar  to  the  one  just  illustrated,  was  used  on  the  Fouillarion 
vehicles,  built  in  France,  but  was  displaced  later  by  a  system  of  toothed 
gear  wheels  of  various  diameters  to  give  the  several  speed  ratios  between 
the  engine  and  rear  axle. 

Types  of  Transmissions. — There  are  four  forms  of  trans- 
missions in  general  use  on  automobiles: 

1.  Progressive; 

2.  Selective; 

3.  Planetary; 

4.  Frictional  Contact. 

Usually,  the  transmission  is  constructed  to  give  three  speeds 
forward  and  one  reverse,  however,  a  few  of  the  large  sized  cars 
have  transmissions  giving  four  speeds  forward. 

Progressive  Transmissions. — With  this  type  of  transmission 
it  is  necessary,  as  its  name  indicates,  to  make  the  various  speed 
changes  in  a  definite  order,  that  is,  in  passing  from  low  to  high 
speed  the  intermediate  speeds  must  be  passed  through  in  regular 
order. 

Fig.  260  is  a  diagram  showing  the  operation  of  a  three  speed 
progressive  transmission.  Power  is  applied  from  the  engine  at 
P  and  delivered  at  T  to  the  driving  shaft.  The  shaft  T  is  squared 
for  a  portion  of  its  length,  and  runs  in  a  bearing  inside  of  the 
gear  C.  The  gears  I  and  L  are  cut  out  of  the  same  piece  of 


TRANSMISSIONS. 


371 


metal  and  fitted  with  a  square  hole  so  that  they  can  slide  along 
the  shaft  P  but  not  revolve  independently  of  it.  The  gears  C',  I', 
and  L/  are  fastened  rigidly  to  the  countershaft  CS  and  there- 
fore revolve  with  it.  The  gear  R  is  an  idler  but  is  so  mounted 
that  it  may  be  shifted  into  mesh  with  L  and  L/  when  a  reverse 
is  desired. 

The  various  speeds  operate  as  follows:  If  C  and  C'  only  be 
in  mesh  and  no  power  is  being  transmitted  to  the  rear  axle,  then 
in  order  to  obtain  the  low  speed,  the  gear  combination  IL,  is 
shifted  so  that  the  gear  L  will  come  into  mesh  with  L'.  The 
drive  then,  is  through  C,  C',  I/,  L,  and  out  through  the  shaft 
axle  T  from  I/  and  L. 


FIG.  260. — Diagram  of  a  three  speed  "progressive"  transmission.  The 
gears  C'.  I'  and  L'  are  fastened  to  the  countershaft  while  I  and  L. 
slide  on  the  square  portion  of  the  main  shaft  T;  R  is  an  idler  and 
is  used  for  reverse.  The  various  speed  changes  are  made  by  alter- 
ing the  position  of  the  sliding  members. 

For  the  intermediate  speed  the  gears  are  shifted  so  that  I  will 
come,  into  mesh  with  I',  L  of  course  being  moved  out  of  mesh 
with  I/.  The  drive  now  is  through  C,  C',  I'  I  and  out  through 
the  shaft  T  to  the  rear  axle.  For  the  reverse,  L,  and  R  are 
shifted  so  that  L  meshes  with  R,  and  R  with  L/.  The  drive,  in 
this  case  is  through  C,  C',  L',  R,  L,  the  introduction  of  the  fifth 
gear  causing  a  reverse  direction  of  rotation  of  the  rear  axle. 


372 


SELF-PROPELLED    VEHICLES. 


For  the  highest  speed,  gears  I  and  L  are  moved  to  the  left  so 
that  they  will  be  in  mesh  with  no  other  gears,  but  a  clutch  cut 
into  the  left  side  of  I  will  fit  into  the  corresponding  clutch  in  the 
gear  C.  This  serves  the  purpose  of  coupling  shaft  T  to  shaft  P, 
and  the  drive  is  then  called  "direct."  This  form  of  transmission 
is  not  used  very  extensively  on  account  of  the  excessive  shaft 
length,  larger  cases  and  bearings,  which  must  be  used. 

Selective  Transmissions. — This  form  of  transmission,  per- 
mits the  operator  to  throw  in  at  will,  any  speed  combination  with- 
in the  range  of  the  transmission ;  thus,  it  is  not  necessary  in  chang- 


FIG.  261. — Diagram  of  a  three  speed  "selective"  transmission.  With  this 
system  any  of  the  several  speed  changes  may  be  made  at  will  with- 
out passing  through  the  intermediate  speeds  as  is  necessary  with 
a  progressive  transmission. 

ing  from  low  to  high  speed  to  pass  through  the  intermediate 
speed  as  with  the  progressive  system. 

Fig.  261  is  a  diagram  of  a  three  speed  selective  transmission 
showing  its  operation.  This  gearing  consists  of  two  parallel 
shafts,  T  and  CS,  the  countershaft  CS  having  keyed  to  it  the 
g^ars  C',  I',  L/  and  R',  the  latter  a  squared  shaft  T  carrying 
the  gears  I  and  L.  Gear  G  is  an  "idler"  used  for  obtaining  the 


TRANSMISSIONS. 


373 


reverse.  P  is  a  driving  shaft  directly  connected  with  the  engine 
through  the  clutch.  Its  gear  C  runs  free  on  the  shaft  T,  and  is  in 
mesh  with  gear  C'. 

Taking  first  the  low  speed  position,  the  drive  is  from  C  to 
C'  to  L  through  LA  On  the  intermediate  speed,  L  is  thrown  out, 
and  I  is  thrown  into  mesh  with  I'.  For  high  speed  the  claw 


H 


,H 


tflCH 


^-Q 


FIG.  262. — Diagram  showing  the  various  positions  of  the  change  speed 
gears  of  a  three  speed  selective  transmission.  It  should  be  noted  that 
this  type  is  of  different  construction  from  that  shown  in  fig.  261. 
Both  are  described  in  detail  in  the  text. 

clutch  on  I  is  slid  into  mesh  with  a  corresponding  clutch  on  C.  The 
drive  in  this  case  is  direct,  going  from  P  directly  out  through  T, 
the  gears  C  and  I  being  locked  by  the  clutch.  For  the  reverse, 
the  gears  R',  G  and  L  are  in  mesh,  and  as  G  makes  the  fifth  gear 
in  the  system  the  direction  of  rotation  is  reversed.  The  gears  are 
shifted  by  means  of  one  control  lever  which  is  placed  within  easy 
reach  of  the  driver. 


374 


SELF-PROPELLED    VEHICLES. 


Another  three  speed  selective  transmission  is  shown  in  fig.  262.  This 
gearing  consists  of  two  parallel  shafts,  I  and  S,  the  former  having  keyed 
to  it  the  gears  B,  C,  D  and  E,  the  latter,  a  "squared"  shaft  for  carrying 
the  gears  H  and  F.  Gear  G  is  an  "idler,"  used  for  obtaining  the  reverse. 
S  is  a  driving  shaft  directly  connected  with  the  engine  through  the  clutch. 
A  runs  free  on  the  shaft  S,  and  is  in  mesh  with  gear  B. 

Taking  first  the  low  speed  position,  the  drive  is  from  F  to  D  to  A 
through  B. 

On  the  intermediate  speed,  F  is  thrown  out,  and  H  is  thrown  into 
mesh  with  C. 

For  high  speed,  the  gear  H  is  slid  into  mesh  with  an  internal  gear  cut 
into  the  rim  of  A.  The  drive  in  this  case  is  direct,  going  from  S  directly 
out  through  A,  the  gear  H  simply  serving  as  a  clutch. 


FIG.  263. — Diagram  of  a  four  speed  selective  transmission.  This  differs 
from  the  three  speed  only  in  the  fact  that  four  gears  are  used  on 
the  driving-  shaft  instead  of  three,  the  various  gears  being  brought 
into  mesh  as  shown  in  the  illustration. 

For  the  reverse,  the  gears  E,  G,  and  F  are  in  mesh,  and  as  G  makes  the 
fifth  gear  in  the  system,  the  direction  of  rotation  is  reversed. 

In  this  form  of  transmission  the  gears  are  so  arranged  that  any  speed 
may  be  obtained  without  having  to  go  through  any  of  the  others,  and 
therefore  the  one  lever  selective  control  may  be  very  easily  used.  This 
feature  is  appreciated  by  everyone  because  it  makes  the  operation  of 
changing  gears  very  simple,  and  allows  the  car  to  be  easily  handled  on 
crowded  streets  and  on  different  grades. 

Some  of  the  larger  cars  are  equipped  with  selective  transmis- 
sions giving  four  speeds  forward.  A  transmission  of  this  type 
is  illustrated  in  fig.  263. 

The  four  speed  selective  transmission  differs  from  the  three  speed  only 
in  the  fact  that  four  gears  are  used  on  the  driving  shaft  instead  of  three, 
the  various  gears  being  brought  into  mesh  as  shown  in  the  illustration. 


TRANSMISSIONS. 


375 


Jn  the  case  of  a  low  speed,  the  drive  is  through  C,  C',  G  and  D.  The 
second  speed  through  C,  C',  F  and  B.  Third,  through  C,  C',  E  and  A. 
For  the  reverse,  the  reverse  gear  R  is  thrown  into  mesh  with  G  and  D 
making  the  drive  through  C,  C',  G  R  and  D. 

The  various  systems  used  in  modern  cars  are  all  based  on  the 
same  principle  but  differ  in  minor  details  according  to  the  ideas 
of  their  designers.  All  of  them  are  enclosed  in  an  oil  tight  case 
and  run  in  a  bath  of  oil.  The  shifting  mechanism  also  differs 
but  the  same  result  is  obtained,  and  it  is  only  on  account  of 
various  patents  which  cover  these  devices  that  transmissions 
are  not  more  uniform. 


FIG.  264. — A  transmission  case  with  cover  removed,  showing  gears  in 
"neutral  position."  The  parts  are  as  follows:  A,  1st  speed  pinion; 
B,  1st  speed  gear;  C,  2nd  speed  pinion;  D,  2nd  speed  gear;  E,  3rd 
speed  pinion;  P,  3rd  speed  gear;  G  square  portion  of  driving  shaft, 
carrying  A,  C  and  E;  H,  driven  shaft,  carrying  B,  D  and  F;  K,  clutch 
pedal;  L,  geared  striking  fork;  M,  change  speed  lever;  N,  change 
speed  quadrant. 

The  Panhard  Sliding  Gear  Transmission. — As  shown  in 
fig.  265,  it  consists  of  two  shafts,  A  and  C,  the  former  carrying 
on  a  square  portion  the  sliding  sleeve,  B,  upon  which  are  four 
gears  of  varying  diameter.  On  the  shaft,  C,  are  keyed  four 
gears,  whose  diameters  vary  inversely  with  those  on  A.  At  the 
right-hand  extremity  of  the  shaft,  A,  is  carried  the  male  cone  of 


g76  SELF-PROPELLED  VEHICLES. 

the  main  clutch,  which,  when  held  in  gear  by  a  pressure  of  the 
spring,  F,  enables  the  transmission  of  power  direct  from  the 
crank  to  the  shaft,  A.  The  clutch  may  be  thrown  out  by  lever,  E, 
which  acts  to  pull  the  shaft,  A,  to  the  left,  compressing  the  spring, 
F.  The  sleeve,  B,  may  be  shifted  on  the  main  shaft  by  lever,  D, 
which  is  connected  as  indicated.  When  as  in  the  cut,  the  gear, 
B1,  is  meshed  with  the  gear,  C1,  the  car  will  have  its  slowest  speed 
forward,  and  the  act  of  shifting  the  gears  to  the  left  from  that 
position  will  raise  the  speed  at  a  regularly  increasing  ratio;  the 
meshing  of  B2  and  C2,  giving  the  second  speed  forward,  and 
the  other  gears  the  next  two  increasing  speeds.  Similarly,  also, 
in  the  act  of  shifting  the  sleeve  from  the  extreme  left  position, 
when  gear,  B*,  is  meshed  with  gear  C*,  there  will  be  a  similarly 
regular  decrease  of  ratio  in  their  speed. 

The  motion  is  transmitted  from  shaft,  C,  through  the  bevel 
gear,  G,  which,  as  shown  in  both  sections  of  the  cut,  meshes  with 
another  bevel  on  the  transverse  jack  shaft.  This  bevel,  H,  and 
a  similar  bevel,  L,  on  the  case  containing  the  differential  gear, 
are  keyed  to  the  sleeve,  M,  which  works  over  the  centre-divided 
countershaft,  at  two  extremities  of  which  are  the  sprocket  pinions 
for  driving  direct  to  each  of  the  rear  wheels.  As  long  as  the 
bevel,  G,  drives  on  H,  as  shown,  the  motion  of  the  carriage  is  for- 
ward, at  any  speed  determined  by  the  relative  positions  of  the 
shifting  gears  on  the  two  shafts,  B  and  C.  In  order  to  reverse 
the  motion  of  the  carriage,  the  sleeve,  M,  is  shifted  upon  the 
lever,  acting  on  the  spool,  K,  so  that  H  is  pushed  out  of  mesh 
with  G,  and  L  is  thrown  in.  By  this  process,  as  is  obvious,  al- 
though the  rotation  of  G  continues  in  the  same  direction,  the 
movement  imparted  to  L  will  be  the  reverse  of  that  previously 
imparted  to  H.  Thus  the  reverse  has  the  same  number  o_'  speed 
and  power  combinations  as  the  forward  motion. 

It  is  also  obvious  that,  by  shifting  the  sleeve,  M,  a  certain  dis- 
tance, the  driving  connections  to  the  main  shaft,  through  the 


TRANSMISSIONS. 


377 


differential,  /,  will  be  thrown  off  altogether.  This  is  the  opera- 
tion necessary  preceding  the  throwing  on  of  the  brake,  the 
drum  of  which  is  on  the  countershaft,  just  beyond  the  thimble,  H. 


FIG.  265.— Details  of  the  Panhard-Levassor  Change  Speed  Gear. 


On  the  later  models  of  the  Panhard  carriages  a  simplified  vari- 
ation of  the  transmission  gear  is  used,  which  drives  through  a 
single  bevel  gear  on  the  jack  shaft,  constantly  in  mesh  with  the 
bevel  on  the  secondary  driven  shaft,  or  top  shaft, — thus  requiring 
no  shifting  of  the  differential  to  throw  the  reverse  bevel.  A 
third  shaft  set  parallel  to  the  clutch  shaft,  carries  two  spur  gears, 
as  shown  in  the  diagram. 


378 


SHLF-PROPHLLED   VEHICLES. 


At  the  position  shown  in  the  diagram  the  lowest  forward  speed 
is  engaged,  through  the  meshing  of  the  spurs,  A  and  E.  By 
bringing  the  hand  lever  all  the  way  back,  the  sleeve  is  moved  clear 
to  the  right,  and  A  and  H  are  thrown  out  of  mesh.  At  the  same 
time,  the  arm  of  the  sliding  gear  shifter  meets  a  raised  portion 
of  the  reverse  shaft,  as  shown,  pushes  it  to  the  right,  depressing 


B 

J 

K 

S= 

*g 

1 

i 

== 

™1 
1 

FIG.  266. — Sketch   of  the  Improved  Panhard-Levassor  Transmission  and 
Clutch. 


the  spring.  The  spur,  J,  is  then  meshed  with  H,  and  K  with  A — 
the  movement  of  the  main  clutch  shaft  being  thus  transmitted 
to  the  top  shaft  through  the  engagement  and  rotation  of  the  third, 
or  reverse,  shaft. 

The  Packard  Transmission. — The  transmission  of  trie  Pack- 
ard car  is  of  the  same  general  type  as  the  last  two  mentioned, 
except  that  it  is  operated  by  two  levers,  one  for  shifting  the  for- 
ward gears  and  one  for  engaging  the  reverse. 

The  Packard  car  is  driven  by  propeller  shaft  and  bevel  gear 
to  the  rear  axle,  and  possesses  the  uncommon  advantage  of  hav- 
ing the  transmission  to  the  gear,  against  the  axle,  thus  saving  the 


TRANSMISSIONS. 


379 


trouble  and  lost  motion  encountered  with  a  long  propeller  shaft 
direct  to  the  driving  bevel,  and,  according  to  claims,  serving  to 
steady  the  driving  bevel. 


-HIGH    SPEED  (DIRE  CT  qRIVF)  POSITION. 


NEUTRAL    POSITION 


DIRECT  DRIVE  POSITION 


FIG.  267.— Diagram  of  Control  Lovers  and  Transmission  of  the  Packard  Car. 


As  shown  in  the  accompanying  diagram,  it  consists  of  three 
shafts : 

1.  The   drive    shaft   connected   by   a   universal   joint   to   the 
of  sliding  a  sleeve  holding  two  spur  gears. 

2.  The  bevel  pinion  shaft  carrying  a  single  spur  gear  at  its 
inner  end  and  bored  to  serve  as  a  bearing  for  the  drive  shaft. 

3.  The  second  motion  shaft,  to  which  are  keyed  three  spur 
gears,  two  of  them  of  diameters  suitable  to  mesh  consecutively 
with  the  sliding  gears  on  the  drive  shaft,  giving  the  lowest,  in- 
termediate speeds,  and  the  third  constantly  in  mesh  with  the  single 
gear  on  the  bevel  shaft, 


380 


SELF-PROPELLED  VEHICLES. 


The  top  speed  as  in  the  Decauville,  and  other  modern  transmis- 
sions, is  obtained  by  sliding  the  two-gear  sleeve  all  the  way  back 
(to  the  right  in  the  diagram),  so  that  its  teeth  mesh  with  internal 
teeth  cut  in  the  circumference  of  the  bevel  shaft  gear,  thus  mak- 
ing the  drive  direct  from  the  motor.  The  reverse  is  obtained 
when  the  gears  on  the  sliding  sleeve  are  in  the  neutral  position 
(indicated  by  the  dotted  outlines  in  the  cut),  by  operating  the 
short  reverse  lever,  thus  causing  an  idler  pinion,  hung  on  a  bell 
crank  to  be  thrown  into  mesh  with  the  forward  (left)  end. 
of  the  drive  and  top  shafts. 


30 


15  9 

FIG.  268.— The  Pope-Toledo  Transmission. 

The  Toledo  Transmission. — The  transmission  gear  used  on 
the  Pope  Toledo  car  is  somewhat  different  from  those  previously 
described.  As  shown  in  the  accompanying  diagram,  shaft,  2, 
driven  by  the  motor,  communicates  the  power  to  the  sliding  gear 
,  sleeve,  5,  through  the  two  bevel  gears,  3  and  4  Sleeve,  5,  car- 
ries sliding  gears,  7  and  14,  and  the  male  portion  of  the  high- 
speed gear  clutch.  These  parts  are  free  to  move  endwise,  but 
are  prevented  from  turning  independently  by  a  long  feather,  6, 
on  sleeve,  5.  The  sleeve,  5,  is  free  to  turn  on  the  transverse 
transmission,  or  jack,  shaft,  29.  Directly  behind  this  shaft  is  a 
second  shaft,  37,  which  carries,  gears  8,  9  and  15. 


TRAXSMISSIONS.  381 

For  the  first  speed  forward  gear,  7,  is  meshed  with  gear,  8,  and 
the  motion  is  transmitted  by  gear  9,  on  the  second  shaft,  tc  gear, 
10  on  the  Jack  shaft,  29.  The  second  speed  forward  is  obtained 
by  meshing  gears,  14  and  15,  and  transmitting  the  motion  to  jack 
shaft,  29  as  before.  To  obtain  the  third,  or  high,  speed,  the 
sleeve  carrying  gears,  7  and  14,  is  moved  to  the  right,  with  the 
result  that  gear,  14,  acts  against  pins,  13,  disengaging  gear,  10, 
from  the  counter  shaft,  and  engaging  clutch,  16,  making  the 
differential,  56,  and  the  countershaft,  29,  continuous  with  sleeve, 
5,  and  thus  driving  direct  from  bevel,  4.  The  reverse  is  effected 
when  the  gear,  7,  is  moved  to  the  left  and  meshed  with  gear,  18, 
on  the  reverse  shaft,  shown  below  and  between  sleeve,  5,  and 
countershaft,  37.  At  the  same  time,  gear,  8,  is  moved  to  the  left 
against  the  pressure  of  spring,  20,  coming  into  mesh  with 
reverse  pinion,  19.  The  drive  is  thus  from  7  to  18,  through  19 
to  8,  and  thence  through  9  and  10  to  the  countershaft,  29.  The 
lever  quadrant  is  notched  to  show  the  proper  positions  for  the 
several  speeds  described. 

Selective  Spur  Transmissions. — Great  troubles  with  early  slid- 
ing spur  transmissions  lay  in  the  facts  that,  in  shifting  from  high 
to  low  gears,  all  intermediate  speeds  were  engaged;  also,  that 
a  careless  or  inexperienced  driver  was  never  sure  to  fully  engage 
two  spurs,  thus  entailing  considerable  wear  and  breakage  of  gear 
teeth.  To  meet  these  objections  the  "selective-finger"  transmis- 
sion as  it  is  generally  called,  was  devised.  The  earliest  example 
of  this  type  of  gear  was  that  used  on  Cannstadt-Daimler  cars, 
shown  in  accompanying  diagrams.  It  was  the  first  car  to 
use  the  gridiron,  or  H-shaped,  quadrant  slot,  now  so  popular. 
Like  later  forms  of  selective  transmission,  it  affected  all  changes 
of  forward  and  reverse  movements  by  the  use  of  a  single  lever. 
The  slot  used  is  typical. 

The  operation  of  the  common  change-speed  and  reversing  lever 
consists  in  the  use  of  a  double  H-shaped  slot,  or  grid  sector,  so 
that  the  lever  may  be  moved  backward  or  forward  in  any  one  of 
three  parallel  channels,  or  shifted  sideways  from  one  to  another 


382 


SELF-PROPELLED  VEHICLES. 


by  means  of  a  fourth  channel  cut  at  right  angles  to  the  other 
three,  like  the  cross  line  of  the  letter  H. 

The  hand  lever  is  pivoted  to  a  cross  spindle,  which  may  be 
slid  lengthwise  in  its  bearings  whenever  the  hand  lever  is  brought 
to  the  middle  transverse  slot  of  the  grid  sector.  The  four  sliding 
spurs  on  the  square  section  of  the  main  shaft  am  in  two  sections 


FIG.  269.-Transmission  Gear  of  the  Cannstadt-Daimler  Carriage  shown  in  the  last 
figure.  Here,  A  is  the  hand  lever ;  B,  the  gridiron  quadrant ;  C,  a  dog  on  the 
lever  for  throwing  out  the  clutch  in  shifting  the  gears ;  E,  toothed  sector  at  end 
of  A  for  actuating  rack  rods  D  and  F  (see  next  figure) ;  G  and  H,  low  speed  gears 
on  the  clutch  shaft:  J  and  K,  low-speed  gears  on  the  second,  or  driving,  shaft; 
N  and  O,  high-speed  gears  on  the  clutch  shaft ;  L  and  M,  high-speed  gears  on  the 
second  shaft.  Hand  G  are  shifted  on  square  portion  of  shaft  by  rack,  F;  N  and 
O  by  rack,  D. 

of  two  spurs  each.  Each  section  is  shifted  by  an  arm  projecting 
downward  from  a  horizontal  rod  bearing  a  rack  on  the  outer  end. 
Furthermore,  these  two  rack  rods  are  set  side  by  side,  so  that 
a  toothed  sector  on  the  lower  extremity  of  the  hand  lever  may 
engage  either  one  of  the  racks,  operating  either  of  the  two  lower 
speeds  when  the  lever  is  moving  in  the  left-hand  slot,  and  either 


TRANSMISSIONS. 


383 


of  the  two  higher  speeds  when  it  is  moving  in  the  second  slot. 
When  drawn  to  the  backward  position  in  either  slot,  it  operates 
the  lower  of  the  two  speeds,  and,  in  the  forward  position,  the 
higher  of  the  two.  In  order  to  reverse  the  movement  of  the 
carriage,  the  hand  lever  is  brought  to  the  mid-position  on  the 
grid-sector,  shifted  all  the  way  to  the  right,  and  moved  forward. 
This  operation  is  possible  because  the  cross  spindle  to  which  the 
lever  is  pivoted  carries  an  arm  projecting  downward  at  right 
angles,  and  terminating  in  another  toothed  sector,  that,  when  the 
lever  is  slid  over  to  the  right,  as  just  explained,  engages  a  third 

o 


FIG.  270.— Details  of  Side-Shifting  Change  Lever  of  the  Cannstadt-Daimler  Car. 

rack  bar  geared  to  throw  in  the  reverse  pinion,  B  (see  figure  of 
reverse  gear).  The  arm,  K,  in  the  same  figure,  carries  an  up- 
ward turned  slot  in  a  position  to  engage  a  pin  on  the  reverse 
rack-shaft,  so  that,  when  that  shaft  is  slid  forward  by  the  inter- 
working  of  the  rack  and  sector,  the  arm  is  lifted  and  pinion,  B, 
brought  into  position  by  the  operation  of  a  bell-crank.  In  ad- 
dition to  the  toothed  sector  set  at  its  lower  extremity,  the  hand 
lever  has  an  arm  at  right  angles  exactly  at  the  pivotal  point, 
so  that,  when  the  lever  is  brought  to  the  transverse  slot  of  the 
grid-sector,  this  arm  presses  upon  a  bar,  thus  throwing  out  the 
clutch. 


384 


SELF-PROPELLED  VEHICLES. 


The  entire  operation  may  be  understood  from  the  figures  of 
the  reverse  apparatus.  Here,  A  is  the  lever,  pivoted  between 
bearings,  B  and  C.  D  is  the  toothed  sector,  which  may  be  shifted 
to  engage  either  of  the  rack  rods,  E  or  F;  L,  is  a  downward  ex- 
tension from  the  pivot  rod  of  A,  carrying  the  sector,  G,  which 
may  be  slid  into  mesh  with  rack,  H.  By  sliding  rack,  H,  to  the 
right,  as  in  the  cut,  pin,  J,  lifts  the  rod  attached  to  the  curved 
slot,  K,  throwing  in  the  reverse  pinion.  The  manner  of  doing 
this  is  shown  with  the  pinions,  A  and  C,  meshing  with  the  long 
reverse  pinion,  B. 


ITic.  271.  -Transmission  and  Clutch  of  the  Columhia  Light  Car.  A,  spur  gear  oa  the 
clutch  shaft ;  B  and  C,  spurs  on  the  squared  second  shaft,  the  first  shifted  by  fork 
hung  at  H,  by  lever,  H  (last  figure),  the  second  by  fork  at  J  by  lever,  J.  D,  E,  F, 
G,  three-speed  pinions  keyed  to  countershaft ;  K,  pinion  giving  reverse  when  in 
mesh  with  C  and  G ;  L,  clutch. 

The  Columbia  Transmission. — The  selective  transmission  of 
the  Columbia  light  car  closely  resembles  that  used  on  the  Decau- 
ville  in  the  method  of  obtaining  the  several  speeds  and  the  re- 
verse. As  shown  in  the  diagram,  the  driving  shaft  consists  of 
two  parts ;  the  clutch  shaft  carrying  gear,  A,  and  the  sleeve  shaft 
carrying  gears,  B  and  C.  Gears,  A  and  D,  are  constantly  in 
mesh.  The  low  speed  is  obtained  when  gears,  F  and  C,  are 
meshed ;  the  second  speed  with  E  and  B  meshed ;  the  top  speed 
with  B  moved  forward  (to  the  left)  so  as  to  engage  the  claw 
clutch  and  make  a  driving  union  with  A;  the  reverse,  when  C 


TRANSMISSIONS. 


385 


is  moved  backward  (to  the  right),  so  as  to  mesh  with  idler  pin- 
ion, K,  which  is  permanently  meshed  with  G,  This  transmission 
differs  from  the  Decauville  in  the  fact  that  gears,  B  and  C,  are 
moved  independently  by  forks  attached  at  H  and  J,  respectively. 
This  transmission  is  not  controlled  by  a  single  lever  and  gridiron 
quadrant,  but  by  two  levers,  H  and  /,  as  shown  in  the  diagram 
of  the  control. 

As  the  control  is  typical  of  modern  systems,  it  is  worthy  pas- 
sing notice.  The  clutch  controls  foot  pedal,  D,  to  the  left  of  the 


FiG.  272,-Plan  Showing  Lever  and  Control  System  of  the  Columbia  Two-cylinder 
Light  Carriage .  A  is  the  dash ;  B,  foot  accelerator  lever  for  controlling  engine ; 
C,  foot  break  lever;  D,  clutch  lever;  E,  clutch  interlock,  requiring  thatclntch 
be  thrown  before  brakes  are  set;  F,  ignition-timing  lever  on  steering  wheel; 
G.  clutch  interlock ;  H,  second  and  third  speed  lever;  J.  first  speed  and  reverse 
lever;  K,  hub  emergency  brake  lever:  L,  brake  rocker;  M,  expanding  brake  on 
driving  shaft ;  N,  rear  live  axle ;  O,  hub  brake. 

steering  post,  opens  the  friction  clutch,  when  pressed  down,  and 
closes  it,  when  allowed  to  rise.  It  is  fixed  on  a  shaft  having 
a  small  finger,  H,  interlocking  the  foot  brake  lever,  C,  on  the 
right  of  the  steering  post,  so,  that,  when  the  clutch  pedal  is 
pressed  down,  no  effect  is  exerted  upon  the  brake  pedal.  But 
owing  to  a  pin  projecting  in  front  of  the  small  interlock  on  the 
clutch  shaft,  when  the  brake  pedal  is  pressed  down  the  clutch 


386  SELF  PROPELLED   VEHICLES. 

pedal  is  caused  to  go  back  and  release  the  clutch.  The  brake 
connections  run  to  the  rear  and  connect  by  a  bell  crank  level 
to  the  expanding  brake  band  on  the  transmission  shaft  at  M. 
This  brake  is  applied  beyond  all  the  universal  joints  on  the  pro- 
peller shaft  so  that  they  receive  no  braking  strains. 

The  emergency  brake  lever,  K,  also  connects  to  the  clutch  pedal 
by  a  slip  interlock,  G,  so  that,  when  it  is  pressed  down,  the  clutch 
pedal  is  also  pulled  off.  Its  connections  run  aft  and  connect  to 
band  brakes,  O,  on  the  driving  wheel  hubs. 

The  speed  change  levers,  H  and  J,  are  shown  on  the  left  side 
directly  in  front  of  the  emergency  brake  lever.  As  in  this  vehicle 
the  engine  power  is  very  high  in  proportion  to  the  weight  of  the 
vehicle,  ordinary  service  requires  that  the  middle  and  the  high 
gears  are  the  ones  most  used.  They  are  thus  controlled  by  one 
handle,  H,  which  is  made  conspicuous.  For  such  backing  and  fill- 
ing as  is  necessary  in  turning  in  close  quarters,  other  handle,  A", 
gives  the  reverse  and  low  gear  ahead.  To  set  the  medium  gear, 
the  conspicuous  handle  is  pulled  back  as  far  as  it  will  go ;  for  the 
high  speed  it  is  to  be  pushed  ahead  as  far  as  it  will  go  regardless 
of  notches  or  other  indexes.  A  small  snap  indicates  the  off  posi- 
tion. Similarly,  to  set  the  reverse  gear,  the  second  lever  is  pulled 
back  as  far  as  it  will  go,  and,  to  set  the  low  gear  ahead,  it  is 
pushed  forward  to  the  end  of  the  slot.  One  lever  cannot  be 
moved  unless  the  other  is  in  the  off  position, 

The  Knox=Mercedes  Transmission. — A  form  of  transmis- 
sion introduced  on  the  Mercedes  car,  and  adopted  on  the  Knox 
vehicles  in  the  United  States,  represents  a  type  worthy  careful 
attention.  As  shown  in  the  accompanying  diagram,  the  main 
shaft,  A,  of  large  diameter,  has  four  spur  gears,  C,  D,  H,  sliding 
on  fluted  keys  or  feathers  integral  with  the  shaft.  It  is  coupled 
directly  to  the  clutch  shaft,  and  runs  in  bearings,  PP.  The  sec- 
ond motion  shaft,  B,  runs  in  bearings,  P1/31,  and  has  gears,/7,  G, 
H,  rigidly  secured  on  it.  The  differential  gears  are  enclosed  in 
the  perforated  case,  M,  and  brake  drum,  N,  is  firmly  secured  to 
the  case.  Two  bevel  gears  are  secured  to  periphery  of  M,  one 
of  which,  L,  is  the  direct  high  gear  drive,  meshing  with  pinion, 


TRANSMISSIONS.  387 

I,  and  the  other  is  the  drive  for  lower  speeds,  meshing  with  pin- 
ion, J,  on  the  second  motion  shaft.  Bevel  pinion,  /,  is  integral 
with  internal  gear,  V ,  and  runs  on  ball  bearings  on  shaft,  A,  ex- 
cept when  it  is  clutched  to  this  shaft  by  sliding  the  gear  E,  into 
mesh  with  V ,  by  means  of  fork,  Q,  and  shifter  bar,  F*,  giving 
fourth  speed  on  direct  drive.  On  this  drive  bevel  gears,  7  and 
K,  and  shaft,  B,  are  running  idle  and  gears,  F,  G,  H,  are  not  in 
mesh.  Meshing,  E,  with  H,  gives  the  third  speed. 


FIG.  273.— The  Knox-Mercedes  Selective  Finger  Transmission,  showing  method  of 
shifting  gears  by  three  shifter  bars,  Y»,  Y»,  Y,,  and  of  driving  through  two  bevel 
gears  to  the  jack  shaft. 

By  means  of  fork,  R,  and  shifter  bar,  F2,  D  is  meshed  with 
G  for  second  speed  or  C  with  F  for  first  speed,  C  and  D  being 
integral. 

The  reverse  gear  is  mounted  between  two  supports  on  the 
bottom  of  case,  and  is  shifted  by  fork,  S\  and  shifter  bar  F1,  into 
mesh  with,  C  and  F  for  the  reverse  motion. 

The  bars  are  shifted  by  a  single  hand  lever  working  in  a  gate 
quadrant  on  the  selective  system.  The  selector  box  is  dust  proof 
and  contains  a  simple  device  which  positively  locks,  in  their  neu- 
tral position,  all  the  shifter  bars  except  the  one  in  use.  On 
direct  drive  none  of  the  gears  on  the  shaft,  B,  are  in  mesh  and 
bevels,  /  and  K,  are  running  idle. 


388 


SELF-PROPELLED    VEHICLES. 


The   Haynes=Apperson   Transmission   Gear. — The  Haynes- 
Apperson  transmission  consists  of  two  parallel  shafts,  A  and  B, 


FIG.  274.— The  Haynes-Apperson  Transmission  Gear,  shown  hung  on  the 
crankshaft,  as  in  the  lighter  cars.  The  reverse  is  now  accomplished  by 
a  chain  between  F  and  F',  dispensing  with  the  idler,  V. 

the  former  being  driven  direct  from  the  crank,  or  by  belt  and 
pulley  from  the  main  shaft,  as  in  the  later  models  of  this  carriage, 


TRANSMISSIONS.  389 

and  carrying  four  gears,  C,  D,  E  and  F,  keyed  in  its  length.  The 
countershaft,  B,  also  carries  four  loose  gears,  Cf,  D',  E'  and  F', 
each  of  which  is  bolted  to  a  band  clutch  drum,  as  illustrated  in 
fig.  274.  Each  of  these  brake  drums,  with  its  attached  gear, 
turns  loose  on  a  separate  drum,  G,  which  is  keyed  to  the  counter- 
shaft, all  of  the  attached  gears,  however,  being  able  to  turn 
through  the  motion  imparted  from  their  mates  on  the  main  shaft, 
without  transmitting  power  to  the  driving  mechanism.  As  may 
be  readily  understood,  in  order  to  transmit  power  through  any 
one  of  the  gears  on  the  countershaft,  it  is  necessary  to  make  it 
rigid  with  its  drum,  G.  The  driving  sprocket  is  keyed  to  the  end 
of  shaft,  B,  as  shown-. 

As  will  be  seen  in  the  separate  cut,  each  one  of  the  drums,  G 
carries  two  arms,  H  and  J,  fixed  diametrically  opposite  one  an- 
other. On  the  arm,  H,  is  carried  a  lever  arm,  K,  pivoted  at  L, 
and  having  a  short  angle  of  movement  by  the  attachment  of  its 
pivot  to  the  bearings,  shown  at  M  and  N.  On  the  two  extremi- 
ties of  the  arms,  R  and  /,  are  carried  brackets,  which  hold  the 
leather  brake  band  against  the  circumference  of  the  drum  turning 
loose  on  G.  One  end  of  this  brake  band  is  riveted  to  the  brake 
on  H,  the  other  to  a  forged  strap,  P,  having  at  its  extremity  the 
lug,  Q,  through  which  works  the  adjusting  screw,  R,  whose  point 
bears  against  the  dog,  S.  This  dog.  S,  is  carried  on  the  square 
section,  T,  of  the  shaft  attached  to  the  lever  arm,  K,  already  men- 
tioned ;  so  that  a  slight  movement  of  the  lever,  K,  to  the  left,  is 
imparted  to  the  dog,  S,  whose  point  bears  against  the  screw,  R,  on 
the  lug,  Q;  thus  drawing  the  strap,  P,  tight  around  the  drum, 
which  is  thereby  made  rigid  with  the  sleeve,  G,  keyed  to  the  shaft, 
B.  By  this  means  the  gear  attached  to  that  particular  drum  im- 
parts the  motion  transmitted  to  it  from  its  mate  on  the  shaft,  A, 
to  the  countershaft,  B,  such  motion  varying  in  speed  according 
to  the  ratios  between  the  meshed  gears.  The  act  of  giving  the  re- 
quired axial  movement  to  the  lever  arm,  K,  is  performed  as  fol- 
lows: 

The  sleeve,  W ',  sliding  on  the  countershaft,  B,  carries  four  fin- 
gers, C",  D",  E",  F",  of  differing  length,  as  shown  in  the  fig- 
ures. In  the  extremity  of  each  of  these  fingers  is  a  lug,  such  as 
is  shown  at  X  and  Y,  the  object  of  which  is  to  engage  the  point 
of  the  lever,  K,  on  some  one  of  the  four  arms,  Ht  thus  causing 
it  to  move  its  dog,  5**  and  tighten  the  brake  band,  as  already  ex-- 


390  SELF-PROPELLED    VEHICLES. 

plained.  In  order  to  accomplish  this  act  without  interference,  the 
positions  of  the  levers,  K,  and  of  the  dogs,  S,  differ  in  each  brake 
drum.  On  drum,  C',  for  example,  it  is  at  the  top  of  the  shaft; 
in  £'  it  is  at  the  bottom;  while  in  D'  and  F'  it  is  on  the  right 
angle  in  either  direction.  For  this  reason',  as  may  be  understood 
from  the  cut,  the  four  fingers  carried  on  the  sleeve,  W ',  are  simi- 
larly disposed,  in  order  that  their  lugs,  X  or  Y ' ,  may  engage  the 
point  of  the  particular  lever,  K,  which  it  is  intended  to  actuate, 
without  interference.  In  order  that  the  fingers,  K,  may  slide 
through  the  drums,  G,  keyed  to  the  shaft,  B,  four  suitable  chan- 
nels penetrate  the  entire  series  of  drums,  G,  as  shown  at  Z  in  one 
of  the  cuts. 

The  sliding  sleeve,  W ,  is  shifted  by  a  lever  working  on  the 
thimble  on  its  outer  extremity,  and  by  causing  its  fingers  to  pene- 
trate the  channels,  Z,  more  or  less,  can  give  three  speeds  forward 
and  a  reverse.  The  reverse  is  accomplished  when  the  lug  on  the 
finger,  F",  engages  the  lever,  K,  on  the  sleeve,  G,  belonging  to 
drum  and  gear,  Ff,  which  act  enables  the  motion  of  pinion,  F,  on 
shaft,  A,  to  be  transmitted  through  the  idler,  V,  to  F',  which  will 
of  course,  rotate  in  an  opposite  direction  to  F,  thus  reversing 
the  motion  of  the  shaft,  B.  In  more  recent  models  of  this  gear, 
F  and  F'  are  sprockets  and  are  connected  by  a  chain  belt,  which 
accomplishes  the  end  of  reversing  the  travel  of  the  carriage  to 
better  advantage  than  by  the  use  of  the  idler,  V.  The  lever  oper- 
ating the  speed-changing  works  through  a  bell  crank  to  spool, 
W. 

The  Brush  Planetary  Transmission. — This  transmission  has 
two  forward  speeds  and  one  reverse  as  shown  in  fig.  275.  In 
order  to  relieve  the  bearings  of  unnecessary  work,  two  bronze 
discs  are  provided  riveted  to  the  low  speed  and  reverse  elements 
indicated  as  A  and  B  to  the  right  of  the  figure.  Between  the 
discs  A  and  B  is  placed  a  ring  with  finished  ends  and  which  fits 
freely  in  a  bore  in  the  housing.  The  two  members  of  the  hous- 
ing also  have  finished  ring  surfaces  which  present  themselves  to 
the  outer  surfaces  of  these  bronze  rings.  The  ring,  marked  C  in 
the  drawing,  has  bolted  to  it  a  lever  which  extends  through  a 
slot  in  the  wall  of  the  housing  and  is  connected  to  the  control 
mechanism  by  linkage  in  such  a  way  that  it  may  be  made  to  rotate 


TRANSMISSIONS.  391 

in  either  direction  within  its  bore  in  the  housing,  depending  upon 
the  direction  of  the  motion  imparted  to  the  control  lever  at  the 
side  of  the  car.  As  shown,  there  are  two  short  spiral  slots  cut 
in  the  cylindrical  surface  of  the  ring  C.  Into  these  slots  fit  two 
rollers  carried  on  spindles  attached  to  screw  plugs  inserted  in  the 
sides  of  the  case. 

The  operation  is  as  follows :  the  bronze  discs,  A  and  B,  revolve 
in  opposite  directions  when  the  engine  is  running  idle,  as  indicated 
by  the  arrows  in  the  detail  sketch.  If  now  the  ring  C  be  rotated 
by  its  linkage  in  a  downward  direction,  the  same  as  that  of  the 
disc  A,  it  will  move  toward  the  left  at  the  same  time  and,  as  the 


FIG.  275,-Sectional  view  of  the  Brush  enclosed  planetary  change  gear. 
This  change  gear  forms  a  unit  with  the  jack  shaft  and  is  suspended 
from  the  side  frame  members  by  the  jack  shaft  brackets  and  in 
front  at  a  single  point,  thus  giving  a  three  point  suspension. 

motion  is  continued,  will  engage  the  disc  A  and  finally  force  it 
into  engagement  with  the  stationary  surface  X  of  the  housing. 

If  it  be  rotated  in  the  opposite  direction,  disc  B  will  be  engaged 
and  finally  held  stationary. 

In  operating  the  car,  it  is  usual  to  fully  engage  these  clutches 
at  once  by  means  of  the  side  lever ;  but  since  the  case  is  filled  with 
oil  and  the  rotation  of  the  bronze  discs  fills  the  spaces  between 
the  engaging  surfaces  with  oil,  due  to  centrifugal  action  upon 
the  oil,  the  engagement  is  not  nor  cannot  be  made  harsh.  The 
rear  transmission  member  of  the  change  gear  is  made  up  of  I,  a 
shaft,  2,  a  bevel  driving  pinion  and  3,  a  large  internal  gear,  keyed, 
riveted  and  pinned  to  form  a  unit. 


393 


SELF-PROPELLED    VEHICLES. 


Transmission  Gear  Ratios. — When  a  car  is  fitted  with  a 
selective  transmission,  the  skill  of  the  operator  must  be  such  as 
to  enable  him  to  determine  the  proper  gear. 

Just  what  the  gear  ratio  should  be  is  a  matter  which  depends  upon  the 
several  conditions  as:  (a)  The  speed  of  the  motor  as  it  relates  to  the 
attainable  speed  of  the  car;  (b)  The  ultimate  speed  of  the  car;  (c)  The 
rate  at  which  acceleration  is  to  be  engendered;  (d)  The  design  of  the 
motor,  taking  into  account  the  torque  curve  of  the  same;  (e)  The  degree 
of  harmony  of  the  several  relations;  (f)  The  competence  of  tires  used. 


PIG.  276. — The  locomobile  four  speed  transmission.  There  are  two  slid- 
ing1 members  moving'  on  the  squared  shaft:  K2  carries  two  gears  and 
is  moved  by  the  action  of  the  gear  lever  when  in  the  outer  slot;  81 
carries  one  gear  and  part  of  a  jaw  clutch  and  is  moved  by  the 
action  of  the  gear  lever  when  in  the  inner  slot.  1st  and  2nd  speeds 
and  reverse  are  obtained  by  moving  82:  1st  speed,  gear  lever  is 
shifted  as  far  forward  as  it  will  go  in  outer  slot  (without  pressing 
button  on  top);  this  meshes  82  with  E.  2nd  speed,  lever  in  rear  posi- 
tion outer  slot;  this  meshes  82  with  D.  Reverse  lever  is  moved  to 
extreme  forward  position  in  outer  slot  by  pressing  button  on  top; 
this  meshes  82  with  G,  an  idle  pinion  driven  by  F.  Third  and  fourth 
speeds  are  obtained  by  the  movement  of  81:  gear  lever  in  forward 
position,  inner  slot,  meshes  81  with  C,  giving  third  speed;  gear  lever 
in  rear  position,  inner  slot,  causes  the  jaw  clutch  on  8  to  lock  with 
the  clutch  pinion  A,  giving  four  speed  and  direct  drive. 

With  four  speeds  the  geometrical  relation  of  the  three-speed  sys- 
tem would  be  retained  and  the  fourth  speed  would  be  interjected 
between  the  second  and  the  third  of  the  three-speed  system,  so  that  the 
third  speed  would  become  the  fourth,  in  a  four-speed  system. 

if  the  power  of  the  motor  be  barely  sufficient  for  the  purpose,  it  is  plain 
that  the  second  speed  should  be  nearer  the  third  speed,  and  the  practice, 
in  general,  is  to  favor  the  motor  in  this  way.  On  the  other  hand,  if  the 
motor  be  of  adequate  power,  it  is  then  that  the  second  speed  can  be  in  the 
geometrical  relation,  and  this  is  an  advantage  on  very  bad  roads,  in  that 
the  low  gear  is  so  advantageously  related  as  to  afford  adequate  advantage 


TRANSMISSIONS. 


393 


under  the  most  severe  conditions,  while  the  second  gear  will  be  high 
enough  to  handle  quite  bad  roads  at  a  fair  speed  in  miles  per  hour  of  the 
car.  The  bevel  drive  can  have  several  ratios,  depending  upon  circum- 
stances.  The  ratio  is  as  follows:  (a)  3  to  i  in  light  roadster  work;  (b) 
3 V*  to  I  in  light  touring  car  work;  (c)  4  to  i  in  heavy  touring  car  work. 


FIG.  277.— The  Winton  1910  multiple  disc  clutch  and  transmission.  The 
clutch  has  sixty-seven  steel  friction  surfaces,  thirty-three  attached 
to  the  transmission  shaft  and  thirty-four  to  the  driving  spiders 
which  are  connected  to  the  flywheel.  The  transmission  is  of  the 
selective  type,  four  forward  speeds  and  reverse.  Direct  drive  on  the 
third  speed,  througn  internal  and  external  gear  combination.  Lock- 
out on  fourth  speed.  The  construction  is  such  that  it  is  possible  to 
enter  neutral  position,  but  impossible  to  engage  any  new  set  of  gears 
while  clutch  is  engaged. 

In  a  general  way  it  is  considered  that  the  sliding  gears  (assuming  three 
speeds  ahead)  should  be  geometrically  related  in  the  manner  as  follows: 


MILES  PER  HOUR 

First.                           Second.  Third. 

5  10  20 

6  12  24 

7  14 

8  16  32 

9  18  36 

10  20  40 

11  22  44 

12  24  48 
15  30  60 
20  40  80 
26  50  100 


In  a  four-speed 
transmission  the 
third  speed  would 
be  as  follows: 

15 

18 

21 

24 

27 

30 

33 

36 

45 

60 

76 


CHAPTER  THIRTY. 

ON    THE    CONSTRUCTION    AND    OPERATION     OF    BRAKES    ON 
MOTOR  CARRIAGES. 

General  Requirements  in  Brakes.— An  important  subject  in 
connection  with  the  construction  and  operation  of  motor  vehicles 
relates  to  the  brakes  used  for  retarding  the  movement  of  the  car- 
riage when  it  is  desirable  to  either  come  to  a  more  or  less  sudden 
stop,  or  to  hold  the  carriage  stationary  on  the  side  of  an  incline. 
Several  conditions  are  essential  to  the  designing  of  brakes  for 
motor  carriages,  among  which  we  may  mention  ease  and  rapidity 
of  operation  and  the  maximum  of  braking  effect,  with  the  mini- 
mum of  power  exerted  at  the  operating  lever. 

Varieties  of  Construction  in  Brakes. — There  are  two  kinds 
of  brakes  in  familiar  use  on  vehicles  of  all  descriptions :  Shoe 
brakes,  which  operate  by  the  pressure  of  the  contact  surface  or 
shoe  upon  the  periphery  of  the  wheel  tire,  and  drum  brakes, 
which  operate  by  tightening  a  band  around  a  drum,  either  on  the 
hub  of  the  wheel  or  on  the  case  of  the  differential  gear.  Both 
varieties  are  used  to  a  considerable  extent  on  motor  vehicles,  al- 
though most  authorities  agree  that  shoe  brakes  are  unsuitable 
for  use  on  wheels  tired  with  pneumatic  tubes.  The  reason  given 
for  this  opinion  is  that  the  constricting  effort  due  to  pressing  the 
shoe  against  the  tire  is,  like  the  ordinary  shocks  experienced  in 
travel,  largely  absorbed  by  the  tire  itself,  with  the  result  that  it 
is  liable  to  be  rent  or  torn  from  its  attachment  to  the  rim.  On 
the  other  hand,  it  has  been  asserted  by  at  least  one  well-known 
manufacturer  of  motor  vehicles  that  shoe  brakes  may  be  safely 
and  satisfactorily  used  on  pneumatic-tired  wheels,  provided  the 
surface  contact  of  the  shoes  extend  over  a.  sufficiently  extensive 
arc  to  prevent  the  strain  from  being  concentrated  on  small  areas 
of  the  circumference.  This  authority  asserts  that  he  himself  has 
used  a  motor  tricycle  for  several  years,  the  wheels  of  which  are 
equipped  with  a  shoe  brake  constructed  according  to  his  idea. 
The  result  is,  he  states,  that  the  contact  surface  of  the  shoe  has 
been  worn  much  more  rapidly  than  the  tire  surface,  which  seems 
to  suffer  very  little,  if  any,  more  than  would  be  the  case  with  the 

394 


CONSTRUCTION  AND  OPERA  TION  OF  BRAKES.  395 

use  of  any  other  form  of  brake.  Whether  his  experience  in  this 
regard  would  be  borne  out  in  general  practice,  it  is  not  necessary 
to  inquire,  the  fact  being  that  nearly  all  motor  vehicles  at  the 
present  time  operate  with  drum  and  strap  brakes. 

Principles  of  Band  Brake  Operation. — Among  the  advan- 
tages  possibly  to  be  alleged  for  the  drum  and  band  brake  we  may 
enumerate  the  facts  that,  with  ordinary  connections,  they  are 
much  more  readily  operated  and  with  much  greater  effect  while 
on  any  showing  involving  a  minimum  of  wear  on  the  moving 
parts.  As  may  be  readily  understood,  the  operation  of  the  drum 
and  band  brake  is  a  reversed  application  of  the  principle  of 
torque,  as  already  explained  in  connection  with  the  electrical 
motor.  As  there  explained,  if  the  power  acting  upon  a  rotating 
shaft  be  equal  to  the  weight  of  fifty  pounds  constantly  applied, 
and  the  pulley  attached  to  the  shaft  be  twice  the  diameter  of  the 
shaft,  the  available  power  at  the  periphery  of  the  pulley  will  be 
just  one-half  that  exerted  on  the  periphery  of  the  shaft  itself. 
This  statement  is  equivalent  to  saying  that  if  a  rope  carrying  a 
weight  of  fifty  pounds  be  wound  about  a  pulley,  whose  diameter 
is  one  foot,  mounted  on  a  shaft,  whose  diameter  is  six  inches, 
it  will  exactly  balance  a  weight  of  one  hundred  pounds  on  a  rope 
wound  about  the  shaft.  The  constantly  applied  power  of  slightly 
over  twenty-five  pounds  at  the  periphery  of  the  pulley  will  be 
sufficient  to  rotate  the  shaft  against  a  resistance  of  fifty  pounds 
on  the  shaft.  It  thus  appears  that  the  braking  power,  applied 
around  the  periphery  of  the  brake  drum,  is  efficient  in  retarding 
the  momentum  of  a  forward-moving  vehicle  in  very  nearly  the 
inverted  ratio  existing  between  the  diameters  of  the  drum,  or 
pulley,  and  the  rotating  shaft  to  which  it  is  attached.  In  the 
practical  application  of  this  principle,  however,  it  is  obvious  that 
there  must  be  very  definite  limits  to  the  diameter  of  the  brake 
drum,  or  pulley,  beyond  which  it  would  be  undesirable  to  go. 
According  to  the  practice  adopted  by  light  motor  vehicle  manu- 
facturers, the  average  diameters  of  brake  drums  range  between 
eight  inches  and  two  feet,  the  principal  item  of  variation  in  this 
respect  being  the  weight  of  the  vehicle  itself. 

Beaumont's  Formulas  for  Brakes. — It  is  possible  to  obtain  a 
very  efficient  band  brake  on  a  very  moderate  diameter  of  drum, 


396  SELF-PROPELLED   VEHICLES. 

owing  to  the  fact,  which  need  scarcely  be  mentioned,  that  the 
braking  effort  is  never  applied  until  the  motive  power  is  discon- 
nected from  the  running  gear.  In  a  steam  vehicle,  the  first  act  is 
to  shut  off  the  steam  from  the  cylinder ;  in  a  gasoline  vehicle,  to 
throw  off  the  main  clutch;  in  an  electrical  vehicle,  to  open  the 
circuit  of  the  motor  and  batteries.  The  resistance  against  which 
the  brake  must  then  operate  is  found  to  be  purely  a  consideration 


FIG.  278.-TheHub  Brake  and  Operating  Levers  Used  on  the  Panhard  Carriages.— The 
arm,  F,  being  pushed  in  the  direction  of  the  arrow,  causes  the  arm,  G,  on  the  same 
pivot,  H,  to  move  in  the  opposite  direction,  as  indicated  by  the  lower  arrow.  Through 
this  arm,  G,  runs  the  cable,  J,  as  shown,  which,  pulling  on  the  arm,  K,  pivoted  at  I, 
pulls  the  strap,  shown  by  dotted  lines  around  the  drum,  S.  The  other  end  of  the 
strap  attached  to  the  short  arm  of  the  lever,  K,  is  thus  drawn  toward  the  same  point; 
a  tight  frictional  bind  being  the  result. 


of  the  vehicle's  weight,  its  velocity  and  the  acceleration  due  to 
gravity.  This  principle  is  already  stated  by  Mr.  Beaumont,  as 
follows : 

"When  it  is  necessary  to  determine  the  brake  power  to  stop  a 
vehicle  of  a  given  weight  running  at  a  given  speed,  in  a  given 
distance,  and,  by  this  means,  arrive  at  something  like  due  com- 
prehension of  the  necessary  parts  brought  into  play  to  effect  this 
stop,  it  must  first  be  pointed  out  to  those  who  overlook  the  fact, 
that  the  strain  put  upon  a  brake  to  effect  a  stop  in  a  given  dis- 
tance increases  as  the  square  of  the  increase  of  speed;  so  that 
to  stop  a  car  running  twenty  miles  per  hour  requires  four  times 


CONSTRUCTION  AND  OPERA  TION  OF  BRAKES. 


397 


the  power  necessary  to  stop  it  in  the  same  distance  when  run- 
ning ten  miles  per  hour.  Commonly,  all  calculations  relating  to 
the  acceleration  of  masses  at  high  speed  are  calculated  on  the 
basis  of  distance  covered  in  feet  per  second,  and  hence  the  work 
or  energy  lodged  in  a  mass  having  a  given  weight  and  moving 
at  a  given  velocity  in  feet  per  second  is  given  by  the  following 
expression : 

W  v2 


in  which  K  represents  the  work,  or  energy,  lodged  in  the  mov- 
ing mass ;  W  represents  its  weight ;  v,  its  velocity,  expressed  in 


Fro.  279.  FIG.  280. 

FiGS.279and  2SO.-Two  Forms  of  Constricting  Band  Brake.  In  the  first  figure,  the  drum, 
E,  rotates  on  the  spindle,  D.  Two  shoes,  F  and  G,  joined  to  the  link,  L,  pivoted  at  J, 
are  pressed  against  the  periphery  of  the  drum,  E,  when  the  link,  K,  moves  the  lever, 
H,  pivoted  at  C,  so  as  to  pull  the  arm,  A,  on  F,  by  compressing  the  spring,  B,  normally 
holding  them  apart. 

In  the  second  figure,  the  band,  D,  surrounding  the  drum,  G,  is  drawn  tight,  when  the  link, 
A,  operates  the  bell  crank,  B,  thus  producing  a  pull  through  its  attachments  at  C 
and  E. 

feet  per  second,  and  g,  the  acceleration  due  to  gravity,  or  32.2 
feet  per  second." 

From  the  above  formula,  Mr.  Beaumont  proceeds  to  derive 
other  essential  dements,  such  as  the  efficient  power  necessarily 


398  SELF-PROPELLED    VEHICLES. 

applied  to  stop  a  vehicle  of  given  weight,  in  a  given  length  of 
travel. 

Reducing  the  expression  for  feet  per  second  to  miles  per  hour, 
according  to  the  usual  standard,  and,  assuming  the  weight  of  the 
vehicle  to  be  one  ton  (of  2,240  pounds),  he  reduces  the  formula, 
as  follows  :  One  mile  being  5,280  feet,  and  one  hour,  3,600 
seconds,  ^ 

1  mile  per  hour  =  -  ^—  =  1.466  feet  per  second. 

o,  uOU 

Whence  W  v2          W   X    (1.466)2  _    W   X   2.15 
~2T  64.4  64.4 

Then  a  vehicle  weighing  one  ton,  traveling  at  ten  and  twenty 
miles  per  hour,  by  the  formula, 

K=  W  V*X  0.0334, 

in  which  F  represents  miles  per  hour,  will  be  for  10  miles 
2,240  X  100  X  0.0334  =  7,480  foot  pounds;  for  20  miles 
2,240  x  400  X  0.0334  =  29,920  foot  pounds. 

To  Find  Distance  in  Which  Brakes  Will  Act  on  Vehicle's 
Speed.  —  Then,  taking  k  as  the  coefficient  of  friction  between  the 
tires  and  road  surface,  which  is  approximately  0.60  for  rubber 
tires  ;  and  taking  w  as  the  proportion  of  the  total  weight  carried 
by  the  wheels  to  which  the  brake  is  applied,  which  may  be  as- 
sumed to  be  0.6  of  the  whole,  the  maximum  distance  required  to 
stop  the  vehicle  on  the  level,  on  an  ordinary  road,  whose  surface 
resistance  is,  supposedly,  included  in  the  expression,  k,  may  be 
expressed  by  /,  as  follows  : 

_  W  V2  X  0.0334 

I   —  ; 

K    W 

Then,  for  a  vehicle  weighing  one  ton,  tired  with  average  rub- 
ber tires,  traveling  at  a  momentum  of  10  and  20  miles  per  hour, 
respectively,  we  have  : 

I  =  O6'^4810344  =     9.3  feet  at  10  miles,  and 


these  distances  representing  the  maximum,  with  a  braking  effect 
sufficient  to  cause  the  wheels  to  skid. 


CONSTRUCTION  AND  OPERATION  OF  BRAKES. 


399 


To  Find  the  Required  Braking  Pull. — In  order  to  find  the 
necessary  pull,  p,  on  the  brake  band,  the  following  formula  is 
given : 

WV2  X  .0334 


=  Tc  10  = 


I 


which  for  one  typical  vehicle,  moving  at  20  miles  per  hour, 
gives, 

29,920 


P 


37.1 


=  806  pounds. 


Fio.  281. 


FIQ.  282. 


FlOS.  281  and  282.  Two  Forms  of  Expanding  Band  Brake.  In  the  first  figure,  the  gear,  G, 
nas  an  internal  bearing  surface,  within  which  is  the  band,  C,  pivoted  at  A,  a  point 
separate  from  G.  The  arm,  B,  of  the  bell  crank,  B  D,  being  moved  to  the  left,  spreads 
apart  the  two  links,  E  and  F,  connected  to  D  at  H,  thus  pressing  both  ends  of  the 
band,  C,  against  the  internal  bearing  surface  of  G,  and  producing  the  necessary  brak- 
ing friction. 

In  the  second  figure,  the  gear,  A,  similarly  arranged  with  an  internal  bearing  surface, 
contains  the  expanding  band,  B.  When  the  link,  C,  is  pulled,  the  lever  arm.  D,  double- 

Eivoted  at  E  and  F,  causes  the  two  ends  of  the  band,  B,  to  press  against  the  internal 
earing  surface  of  A,  thus  creating  friction.    The  spring  shown  normally  holds  the 
two  ends  of  the  band  apart. 

Varieties  of  Drum  and  Band  Brake. — As  shown  by  accom- 
panying illustrations,  there  are  two  general  types  of  drum  brake, 
the  first  consisting  of  a  drum  or  pulley,  around  the  circumfer- 
ence of  which  is  a  metal  strap  faced  with  leather,  which  is  drawn 
tight  whenever  it  is  desired  to  furnish  the  resistance  necessary  to 
check  the  rotation  of  the  shaft;  and  expanding  band  brakes,  in 
which  a  similar  metal  strap,  faced  with  leather  or  other  suitable 
substance  acts  against  the  internal  surface  of  a  rotating  drum  or 
pulley.  The  former  type  is,  however,  at  the  present  time  the 
most  usual  construction,  although  the  latter  is  seeing  an  increas- 
ing popularity. 


400 


SELF-PROPELLED    VEHICLES. 


In  some  forms  of  constricting  band  brakes,  instead  of  a  metal 
strap  extending  entirely  around  the  drum,  two  shoes  pivoted  at 
a  certain  point,  and  having  their  inside  faces  faced  with  leather, 
are  tightened  against  the  drum  by  a  suitable  lever.  In  practically 
all  forms  of  expanding  band  brake  the  band  is  attached  to  the 
outside  frame,  at  one  point  of  its  circumference,  and  is  suitably 
tightened  by  a  toggle  joint  operated  by  a  lever. 

The  Care  of  Brakes. — In  successfully  operating  a  motor  car- 
riage it  is  particularly  essential  that  the  brakes  should  be  main- 
tained in  good  working  order.  This  involves  that  the  levers  and 


FIGS.  283  and  284. — The  Locomobile  brakes.  The  running1  brake  consists 
of  a  contracting  band  brake,  the  pulley  of  which  is  located  on  the 
differential  shaft  at  the  right  of  the  bronze  gear  case  and  to  which 
the  band  is  firmly  secured.  This  brake  is  of  the  double-acting  type, 
12  inches  in  diameter  and  4  inches  wide.  The  brake  pedal  is  operated 
by  the  right  foot  and  when  the  brake  is  engaged  the  clutch  is  not 
automatically  disconnected.  The  halves  of  the  brake  band  are 
hinged  at  the  rear  and  are  adjusted  in  front  by  two  turn-buckles;  it 
has  also  a  set-screw  underneath,  allowing  the  band  to  be  adjusted 
so  that  it  is  free  around  the  circumference  of  the  pulley,  preventing 
any  binding  when  not  in  use.  The  emergency  brakes  are  located  on 
the  rear  wheels,  being  of  the  internal  expansion  variety,  one  to  each 
wheel.  These  are  hinged  at  the  top  and  when  the  hand'  brake  lever, 
placed  at  the  right  of  the  car,  is  pulled  backward,  suitable  mechan- 
ism causes  the  brake  shoes  to  be  expanded  against  the  circumfer- 
ence of  the  brake  drum:  when  the  lever  is  released,  springs  draw 
the  bands  away  from  the  circumference  of  the  drum. 

connections  should  at  all  times  operate  perfectly,  and  that  no 
worn  or  loose  bearings  should  be  neglected.  Furthermore,  and 
most  important,  the  friction  surface  between  the  band  and  the 
drum  should  be  constantly  and  carefully  guarded  from  oil  de- 
posits, which  will  certainly  render  the  braking  effort  useless.  If 
oil  collects  between  the  band  and  the  drum  surface  it  may  be  cut 
out  with  gasoline,  and  the  parts  then  carefully  wiped  with  a  suit- 
able rag. 


CHAPTER    THIRTY-ONE. 

ON  BALL  AND  ROLLER  BEARINGS  FOR  MOTOR  CARRIAGE  USE. 

The  General  Uses  of  Rotative  Bearings. — The  practical 
problems  involved  in  the  construction  of  bicycles  and  motor  car- 
riages have  given  a  great  popularity  to  ball  and  roller  bearings 
for  use  in  connection  with  almost  every  variety  of  rotating  shaft. 
As  we  have  already  seen  in  several  constructions  mentioned  in 
previous  parts  of  this  volume,  ball  bearings  are  used  in  a  large 
variety  of  different  devices,  in  order  to  allow  of  the  greatest  pos- 
sible ease  in  turning  with  the  smallest  friction  and  wear.  The 
most  important  use,  however,  for  ball  and  roller  bearings,  in  both 
bicycles  and  motor  carriages,  is  on  the  axles  of  the  road  wheels. 
For  this  purpose,  although  ball  bearings  are  eminently  satisfac- 
tory on  the  wheel  axles  and  pedals  of  bicycles,  they  are  for  a 
number  of  reasons  unsuitable  for  the  heavier  weights  and  higher 
speeds  of  motor  carriages.  Accordingly  roller  bearings  have 
taken  their  place  almost  exclusively  in  this  connection. 

Rotating  Supports  vs.  Sliding  Surfaces. — The  principal  ob- 
ject involved  in  using  ball  and  roller  bearings  on  bicycles  and 
motor  carriages  is  to  secure  economy  of  traction  effort,  with  ease 
and  rapidity  of  driving,  as  well  as  a  minimum  of  starting  effort 
at  the  beginning  of  travel.  A  few  simple  principles  will  serve  to 
fully  explain  the  reasons  for  this  fact.  When  we  have  a  plain 
wheel  bearing,  such  as  is  used  on  ordinary  horse  carriages,  con- 
sisting of  a  simple  tapered  boss,  with  a  similarly  shaped  hollow 
axle-box  rotating  around  it,  there  is  a  considerable  effort  neces- 
sary at  starting  from  rest,  a  good  proportion  of  the  power  being 
consumed  in  resisting  the  friction  between  the  sliding  surfaces. 
This  resistance  is  very  largely  due  to  adhesion  between  the  two 
sliding  surfaces,  due  to  cohesion  of  the  lubricating  oil  or  grease. 
As  a  matter  of  fact,  it  may  be  easily  understood  that  the  sliding 
action  of  two  round  surfaces,  one  within  another,  may  be  readily 
compared  to  the  sliding  of  one  plane  surface  upon  another.  The 
first  difference  in  point  of  resistance  and  effort  necessary  to  over- 
come inertia,  as  between  two  such  surfaces,  when  sliding  against 

401 


403 


SELF-PROPELLED    VEHICLES. 


one  another  directly,  and  when  some  kind  of  rollers  or  rotating 
supports  are  interposed,  is  a  matter  of  the  commonest  experi- 
ence. The  heaviest  objects  may  be  readily  moved  or  slid  along 
the  ground  when  rollers  are  placed  beneath  them;  also  the 
heaviest  loads  when  carried  on  wheels  of  suitable  breadth  and 
diameter  may  be  handled  with  a  degree  of  ease,  increasing  di- 
rectly as  the  ideal  conditions  are  approximated.  This  principle  is 
the  very  one  that  is  applied  in  the  practice  of  substituting  ball 
and  roller  bearings  for  ordinary  plain  bearings.  Instead  of  two 
plane  surfaces  having  rollers  interposed,  the  two  surfaces  are 
given  a  rounded  contour,  the  one  being  within  the  other,  and  the 
same  rule  of  increased  ease  of  relative  movement  applies. 


A  i 


Fio.  285.-One  Form  of  Driving  Axle  Using  Ball  Bearings.  The  hub  is  secured  in  place  by 
the  nuts  and  binders  shown  at  A,  B,  C,  D,  E.  At  its  inner  extremity  it  carries  a  cone, 
F,  which  works  on  the  ball  race,  G.  The  hub  is  thus  suspended  on  the  ball  race,  which 
also  acts  to  neutralize  end  thrusts. 

Rotative  Bearings  vs.  Plain  Bearings. — The  obvious  reason 
for  the  superior  traction  qualities  obtained  by  the  use  of  both 
kinds  of  rotative  bearings  is  that  the  friction  and  resistance  be- 
tween the  relatively  moving  surfaces  is  so  greatly  distributed  that 
it  is  reduced  to  a  practically  negligible  quantity. 

One  of  the  most  familiar  evidences  of  loss  in  power  through 
the  friction  of  the  sliding  surfaces,  in  plain  bearing  wheels,  is  seen 
in  the  fact  that  the  hubs  speedily  become  loose,  greatly  to  the 
detriment  of  balanced  rotation  of  the  wheels  and  waste  of  trac- 
tion effort.  With  properly  adjusted  ball  or  roller  bearings  this 
result  is  indefinitely  delayed,  even  where  it  is  not  entirely  obvi- 
ated, and  the  wheels  on  which  they  are  used  not  only  give  the 


BALL  AND   ROLLER  BEARINGS. 


403 


best  results  in  point  of  tractive  efficiency,  but  also  in  the  duration 
of  their  period  of  usefulness. 

Ball  Bearings  and  Their  Use. — The  ball  bearing  was  origi- 
nally introduced  for  use  on  bicycles,  and  contributed  a  goodly 
share  to  its  success,  principally  for  the  reasons  just  specified.  On 
the  introduction  of  the  motor  carriage,  it  found  a  new  field  of 
usefulness,  although,  owing  principally  to  the  poor  metal  used 
for  the  balls  and  the  defective  designs  of  ball  races,  the  roller 


Fto.  286.  Fio.  287. 

Pias.  28 6  and  28 7;— Radial  Ball  races  and  Balls,  showing  most  satisfactory  method  of 
mounting  a  ball  bearing,  lie.  286  shows  the  so-called  "silent  type  "of  bearing, 
having  the  balls  separated  by  felt-packed  springs.  Fig.  287  shows  the  "full'' 
type,  in  which  the  balla  are  la  contact. 

bearing  enjoyed  a  greater  popularity  for  several  years.  The  re- 
appearance of  the  ball  bearing  on  the  motor  carriage  is  to  be  at- 
tributed largely,  if  not  entirely,  to  fact  that  balls  of  superior  and 
uniformly  hardened  steel  have  been  introduced,  which  do  away 
with  the  faults  of  case  hardened  steel — liability  to  crystallizing 
and  crushing,  due  to  inability  to  support  a  concentrated  load  on  a 
single  diameter.  Formerly,  considerable  was  said  about  the  lia- 
bility of  balls  to  roll  in  opposite  directions,  thus  producing  friction 
and  speedy  wear,  faults  doubtless  due  to  poor  designs  of  the  re- 
taining cones  and  ball  races. 

The  prevailing  type  of  ball  bearing  at  the  present  time  is  the 
so-called  "radial,"  as  shown  in  accompanying  figures,  in  which  the 
balls  are  inserted  between  an  internally  and  an  externally 


404 


SELF-PROPELLED  VEHICLES. 


grooved  ring1.  For  the  best  results  only  a  single  row  of  balls  is 
used  in  a  journal,  and  all  uncertainty  and  irregularity  in  sup- 
porting the  load  are  thus  eliminated.  The  radial  ball  bearing  is 
also  capable  of  taking  up  moderate  end-thrust,  although  with 
large  end-thrust  a  special  thrust  bearing,  having  the  balls  running 
in  face  grooves  between  two  plates,  is  used.  The  type  of  bear- 
ing thus  described  is  capable  of  showing  a  nearly  uniform  friction 
coefficient. 


FIG.  288  -Pour- cylinder  Gasoline  Engine,  showing  the  radial  ball  bearings  on  th* 
crank  shaft. 

Roller  Bearings  and  Their  Use. — Very  largely  on  account 
of  the  defects  in  the  earlier  types  of  ball  bearing,  roller  bearings 
were  for  several  years  used  almost  exclusively  on  motor  carriages. 
As  has  been  stated  by  a  prominent  manufacturer  of  roller  bear- 
ings, we  have  it  that  "for  heavy  weights  it  would  seem  that  a 
greater  rolling  surface  must  be  obtained  before  we  can  have  a 
successful  bearing,  and  yet,  combined  with  this  greater  rolling 
surface,  there  must  be  a  purely  rolling  action  to  eliminate  the 
wear  that  results  from  rubbing  and  crystallization." 

As  stated  by  a  noted  authority,  the  peculiar  advantage  of  the 
roller  bearing  lies  in  the  fact  that  in  the  ideal  conditions  there  is 
no  relative  sliding,  and,  therefore,  theoretically,  no  friction.  As 
also  stated  by  him,  however,  there  are  several  difficulties  in  the 


BALL  AND  ROLLER  BEARINGS. 


405 


way  of  obtaining-  the  theoretically  perfect  conditions  in  practical 
operation.  These  are:  (i)  the  concentration  of  the  load  upon 
points ;  (2)  the  almost  insurmountable  difficulty  of  obtaining  truly 
circular  cylindrical  rollers ;  (3)  the  friction  on  the  surfaces  of  the 
rollers  themselves;  (4)  the  difficulty  of  adjustment;  (5)  the  lack 
of  parallelism  when  the  rollers  are  slightly  worn ;  (6)  the  difficulty 
of  providing  for  end  thrusts  or  side  pressures ;  (7)  the  blows  and 
shocks  resulting  when  wearing  has  occurred  on  the  surfaces  of 
the  rollers.  He  further  explains  that  to  any  extent  whatever, 
however  small,  that  the  surface  of  contact  deviates  from  the 
theoretical  or  geometrical  line,  the  action  between  the  two  sur- 
faces deviates  from  the  theoretically  perfect  rolling  contact,  in- 
volving sliding  or  frictiotnl  contact  proportionate  to  the  de- 
formation of  the  roller. 


P^G.  289.— The  "Hyatt"  Flexible  Roller  Bearing,  which  consists  of  strips  of  stee. 
rolled  into  coiled  springs,  forming  a  strong,  though  elastic,  support,  and  capable 
of  taking  some  end  thrust. 

Constructional  Points  on  Roller  Bearings. — Given  the  best 
possible  process  available  to  the  practical  machinist  for  the  needs 
of  adequately  shaping  and  hardening  rollers,  the  problem  of  the 
best  construction  becomes  almost  entirely  one  of  proper  assem- 
bling of  the  several  parts.  As  shown  by  the  accompanying  il- 
lustration, the  usual  method  of  mounting  roller  bearings  is  to 
•enclose  them  in  a  suitable  case,  in  which  the  several  cylindrical 
rollers  are  separated,  so  that,  rotating  on  their  own  axes,  their 
surfaces  do  not  come  into  contact.  It  is  a  very  usual  practice  to 
include  end  thrust  ball  bearings  at  the  extremities  of  the  roller 
cylinders,  so  as  to  still  further  reduce  the  wear  and  friction  inci- 
dent on  the  rotation  of  the  several  cylinders. 

One  of  the  most  excellent  types  of  roller  bearing  for  motor 
carriages  is  the  "American"  roller  bearing,  which,  as  shown  by 


406 


SELF-PROPELLED  VEHICLES. 


the  accompanying  illustrations,  consists  of  a  set  of  main  rollers 
intended  directly  to  sustain  the  weight,  and  running  in  races  on 
the  hub  and  on  the  axle.  These  main  rollers  are  separated  and 
guided  by  intermediate  separating  rollers,  whose  office  is  solely 
that  of  separating  and  guiding.  These  separating  rollers  are  con- 
fined between  the  centres  of  the  main  rollers  and  overlap  their 
ends,  their  action  being  entirely  rolling.  The  supports  of  these 
separating  rollers  are  had  in  three  rings  held  in  place  by  the 
flange  ends  of  the  separators  and  running  in  narrow  beveled 
grooves  in  the  separators  and  in  the  fixed  caps  which  enclose  the 
entire  mechanism.  The  rolling  parts  are  so  arranged  that  the 


FIG.  290.— Sectional  Diagrams  of  the  "  American  "  Roller  Bearing.  These  bearings  are 
beveled  at  the  ends,  as  indicated,  the  bevels  taking  up  the  end  thrusts,  and  are  sepa- 
rated by  smaller  rollers,  one  of  which  is  shown  below  the  larger  figures.  These  sepa- 
rating rollers  do  not  come  into  contact  with  the  rotating  axle. 

separators  engage  their  supports  in  perfect  harmony  with  the 
main  rollers,  traveling  just  fast  enough  to  keep  up  with  them  in 
going  about  the  axle,  thus  avoiding  both  dragging  and  pushing. 
In  this  type  of  bearing  the  end  thrust  is  entirely  taken  by 
bevels,  on  the  principle  of  the  flanges  on  car  wheels,  this  con- 
struction involving  that  there  is  no  rubbing  friction;  the  action 
between  the  ends  of  the  roller  and  bevels,  being  purely  a  rolling 
one,  they  are  thrust  against  each  other.  As  claimed  by  the  manu- 
facturers, the  separators  hold  the  main  rollers  far  better  than  any 
cage  could,  while  the  wear  upon  them  is  practically  negligible, 
the  result  being  that  the  main  rollers  are  never  allowed  to  twist 
around,  as  is  frequently  the  case  in  caged  bearings. 


CHAPTER   THIRTY-TWO. 

ON  THE  NATURE  AND  USE  OF  LUBRICANTS. 

Of  Lubricants  for  Various  Purposes. — One  of  the  most  im- 
portant considerations  in  connection  with  the  operation  of  a 
motor  vehicle,  of  any  power,  relates  to  the  proper  lubrication  of 
the  moving  parts.  As  is  perfectly  evident  on  reflection,  it  is 
necessary  that  all  such  parts  should  be  supplied  with  oil  or  lubri- 
cating grease,  but  it  is  also  a  fact,  not  so  well  understood,  that 
different  kinds  of  lubricant  are  necessary  to  the  different  kinds 
of  mechanisms. 

Of  Lubricants  for  Gasoline  Engine  Cylinders. — Every  re- 
liable dealer  in  lubricants  has  a  specially  prepared  grade  of  oil 
for  a  gas  engine  cylinder,  and  still  another  for  use  in  the  cylinder 
of  a  steam  engine,  and  all  agree  to  the  statement,  that  the  kind  of 
lubricant  suitable  in  one  case  is  wholly  useless  in  the  other.  The 
primary  reason  for  this  distinction  is  that,  as  we  have  seen,  the 
cylinder  of  a  gas  engine  operates  under  a  far  higher  temperature 
than  is  possible  even  in  a  steam  engine,  and  consequently  the 
oils  intended  for  use  in  the  former  case  must  be  of  such  a  quality 
that  the  point  at  which  they  will  burn  and  carbonize  from  heat 
is  as  high  as  possible.  Furthermore,  it  is  essential  in  a  gas  en- 
gine cylinder  that  the  oil  should  be  constantly  supplied,  and  for 
the  purpose  of  properly  meeting  this  requirement  a  number  of 
different  kinds  of  dripping  and  filtering  oil  cups  have  been  de- 
vised and  put  into  practical  use. 

Requirements  in  Gas  Engine  Lubricants. — As  has  been  re- 
peatedly pointed  out  by  gas  engine  authorities,  the  apparently 
long  period  spent  in  finally  perfecting  the  motor  was  due  almost 
entirely  to  the  fact  that  the  subject  of  proper  lubrication  was  not 
fully  understood.  With  the  ordinary  oils,  which  are  sufficiently 
suitable  for  use  in  the  steam  engine  cylinder,  it  was  impossible 
to  obtain  anything  like  a  satisfactory  speed  and  power  efficiency, 
and  only  when  the  superior  properties  of  mineral  oils  were  bet- 
ter understood  was  the  present  high  degree  of  perfection  in  any 

407 


408  SELF-PROPELLED    VEHICLES. 

sense  obtainable.  Even  to  the  present  day  the  question  of  proper 
lubricants  for  gas  engines  is  most  essential,  and,  as  has  been  per- 
tinently remarked,  "the  saving  of  a  few  cents  per  gallon  in  pur- 
chasing a  cheaper  grade  of  oil  for  this  purpose  is  the  most  ex- 
pensive kind  of  economy  imaginable."  The  general  qualities  es- 
sential in  a  lubricating  oil  for  use  on  gas  engine  cylinders  in- 
clude a  "flashing  point  of  not  less  than  360°,  Fahrenheit,  and 
fire  test  of  at  least  420°,  together  with  a  specific  gravity  of  25.8 
and  a  viscosity  of  175." 


FIG.  291.-Section  Through  a  Type  of  Power  Driven  Oil  Pump.  A,  oil  reservoir ;  B» 
dashboard  of  car ;  C,  pulley  driven  by  belt  from  engine  shaft;  D,  gravity  valve 
on  distributor;  E,  outlet  elbow  ;  F,  set  screw  to  regulate  stroke  of  plunger,  I :  G, 
plunger  bracket  bearing  against  eccentric,  which  is  on  the  gear  operated  bj 
worm,  or  endless  screw,  on  the  shaft  of  pulley,  C ;  H,  weight  of  gravity  valve,  D. 
for  holding  outlet  port  normally  closed,  and  rising  under  pressure  of  oil  fron? 
pump ;  I,  plunger  of  pump  drawing  oil  from  reservoir.  A,  through  hall  valve,  and 
expelling  it  through  ball  valve  to  outlet,  E  ;  J.  test  cap  for  testing  flow  of  oil ;  K 
oil  outlet  for  test  cap ;  L,  filling  plug  and  strainer ;  M,  stud  bolt  for  securing 
machine  to  dashboard. 

Some  Objections  to  Organic  Oils. — While  a  number  of  ani- 
mal and  vegetable  oils  have  a  flashing  point,  and  yield  a  fire  test 
sufficiently  high  to  come  within  the  figures  specified,  they  all 
contain  acids  or  other  substances  which  have  a  harmful  effect  on 
the  metal  surfaces  it  is  intended  to  lubricate.  In  addition  to  this, 
their  tendency  to  gum  or  congeal  under  certain  conditions  of 
temperature  or  pressure  render  them  unfit  for  the  purpose  of  gas 
engine  lubrication. 


THE  NATURE  AND  USE  O*  LUBRICANTS. 

The  Use  of  Graphite  as  a  Lubricant. — Many  authorities 
strongly  recommend  the  Use  of  powdered  or  flaked  graphite  in 
the  cylinders  of  explosive  engines  for  the  reason  that  this  sub- 
stance is  one  of  the  most  efficient  of  solid  lubricants,  especially 
at  high  temperatures.  It  has  been  found  especially  useful  in 
some  steam  engine  cylinders  and  in  general  on  the  bearings  and 
moving  parts  liable  to  become  overheated.  According  to  sev- 

c 


Via.  292,-Typlcal  Force-feed  Lubricator,  operating  by  air  or  gas  pressure,  Instead  of 
a  pump.  The  parts  are !  A,  oil  reservoir ;  B.  distributing  pipe  ;  C,  C,  valve  screws 
for  regulating  flow  of  oil  to  parts,  through  leaders.  D  and  D  ;  E,  standpipe  through, 
which  oil  is  forced  by  air  pressure ;  F,  standpipe  admitting  gas  from  crank  case 
of  engine ,  F',  uni9n  for  pipe  from  crank  case;  G,  G,  unions  for  pipes  to  various 
parts  of  the  machinery. 

eral  well-known  authorities,  it  is  well  adapted  for  use  under  both 
light  and  heavy  pressures  when  mixed  with  certain  oils.  It  is 
also  especially  valuable  in  preventing  abrasion  and  cutting  under 
heavy  loads  and  at  low  velocities. 

In  using  graphite  as  a  lubricant,  it  is  positively  essential  to  re- 
member one  thing:  It  is,  as  said,  very  useful  for  certain  pur- 
poses, when  mixed  with  some  liquid  oil  lubricants.  However,  it 
is  impossible  to  use  it  in  connection  with  oils  that  are  to  be  fil- 
tered through  the  small  orifices  of  constant  feed  oil  cups,  as  on 


410 


SELF-PROPELLED  VEHICLES. 


the  cylinders  and  bearings  of  engines.  The  reason  for  this  ib 
that  it  will  not  flow  through  small  holes,  even  when  mixed  with 
very  thin  oil ;  and  the  very  cooling  of  a  bearing  will  cause  the 
graphite,  mixed  with  oil,  to  clog  up  the  oil  hole  to  an  extent  thai- 
may  not  be  remedied  by  the  reheating  of  the  bearing,  after  the 
stoppage  of  the  lubricant.  On  the  same  account,  it  is  essential 
that  the  diameter  of  the  oil  conduit  to  any  moving  part  be  as- 
certained to  be  of  suitable  shape  and  proportions  before  the  use 
of  any  solid  lubricant  is  attempted. 

The  Tests  and  Qualities  of  Lubricating  Oils. — It  is  per- 
fectly possible  to  use  an  oil  having  a  fire  test  at  the  point  already 
mentioned  in  a  gas  engine  cylinder  whose  temperature  at  ex- 
plosion is  nearly  four  times  greater,  because  with  a  properly  ad- 


FIG.  293.-Horizont?l  Cylinder  Oiled  by  Force-feed  Oiler  Distributor.  The  piston  Is 
oiled  when  passing  under  oil  port,  as  shown  by  th«  dotted  outline  The  connect- 
ing rod  is  longitudinally  grooved  on  the  upper  surface,  so  as  to  carry  oil  to  the 
bearings. 

justed  water  circulation  the  burning  and  carbonization  of  the  oil 
is  constantly  prevented.  The  heat-absorbing  action  of  the  jacket 
water  is  also  efficient  in  retaining  at  the  required  point  the  vis- 
cosity of  the  oil — which  is  to  say,  the  quality  of  dripping  at  a 
certain  ascertained  rate  through  a  narrow  aperture  under  press- 
ure. This  quality  virtually  refers  to  the  thinness  of  the  oil.  A 
well-known  manufacturer  of  lubricating  oils  for  gas  engine  cylin- 
ders well  states  the  ideal  qualities  to  be  sought,  as  follows: 
"There  is  no  danger  of  this  oil  burning  or  smoking  in  the  cylin- 
der and  thus  causing  a  carbonaceous  deposit,  which  so  seriously 


THE  NATURE  AND  USE  OF  LUBRICANTS.  41 1 

interferes  with  the  proper  running  of  the  engine.  We  have  re- 
peatedly known  of  this  oil,  when  put  into  a  cylinder  which  had 
not  been  properly  cleaned,  cutting  out  the  carbonaceous  matter 
that  had  accumulated  from  the  use  of  an  inferior  oil,  after  which 
the  cylinder  would  remain  clean  and  polished  by  the  action  of 
the  oil  alone."  Combined  with  these  ideal  elements,  the  claim  is 
made  that  this  particular  variety  of  oil  has  a  very  low  ''cold 
test,"  with  the  very  necessary  insurance  against  congealing,  and 
consequent  delay  and  inconvenience  in  starting  the  engine.  Its 
resistance  to  heat  is  also  placed  at  such  a  figure  that  it  will  not 
become  unusually  thin  as  will  some  qualities  of  oil,  the  reason 
being  that  its  viscosity  is  maintained  at  the  desired  point. 


FIG.  294.— Section  of  the  Ford  Doubie-Opposed-Cylinder  Horizontal  Engine,  showing 
oil  leads  to  the  various  points  from  the  lubricator  operated  by  compressed  air 
from  the  crank  case. 

In  choosing  lubricants  for  any  of  the  moving  parts  of  a  self- 
propelled  road  vehicle  it  is  especially  essential  to  see  that  the 
quality  of  resisting  temperatures,  both  high  and  low,  without 
change  of  useful  consistency,  should  be  present.  An  oil  that  will 
congeal  at  ordinary  low  temperatures,  or  become  thin  at  ordi- 
nary high  temperatures,  is,  of  course,  entirely  unsuitable  for  this 


113 


SELF-PROPELLED  VEHICLES. 


purpose.  Furthermore,  the  quality  of  flowing  freely  from  well- 
adjusted  oil  cups  should  be  assured,  since  the  high  speed  of  auto- 
mobile engines  engendering  a  constant  vibration,  affecting  more 
or  less  the  adjustment,  involves  that  the  oil  supplied  should  be  a 
subject  of  constant  solicitude.  To  state  the  matter  in  a  few 
words,  all  competent  authorities  seem  to  agree  that  the  condi- 
tions of  automobile  operation  require  the  use  of  mineral  oils  on 
all  moving  parts  and  the  avoidance  of  any  mixture  with  animal 


I  GAUGE 


Fia.  295.— Sectional  view  of  the  Pierce  lubricating  system,  showing1  the 
position  of  the  oil  reservoir  relatively  to  the  bearings  to  which  it 
transmits  the  lubricating  fluid  and  the  connection  by  which  the  oil 
.overflow  is  returned  to  the  reservoir. 


or  vegetable  oils,  which,  although  frequently  used  in  stationary 
engines,  cannot  but  result  in  inconvenience,  not  to  say  disaster, 
in  automobile  practice. 

Since  most  manufacturers  of  motors  and  vehicles  furnish  mod- 
erately full  directions  for  dealing  with  the  question  of  lubrication, 
many  of  them  offering  for  sale  brands  of  oil  which  have  been 
carefully  tested  by  themselves,  it  will  be  hardly  necessary  to  add 
more  to  the  principles  already  laid  down. 


THE  NATURE  AND  USE  OF  LUBRICANTS,  4LU- 

Points  on  Lubrication. — The  first  important  consideration  in- 
volved in  preparing  a  carriage  for  a  run  is  to  see  that  the  moving 
parts  are  properly  lubricated.  Every  carriage  or  motor  is  sold 
with  directions  for  providing  for  this  necessity,  the  rate  of  oil 
consumption  and  the  quantity  being  specifically  designated.  The 


Oil  tank 


JZxhaiusl  passage 
Fuanp 


FIG.  296a.-Section  Through  One  Cylinder  of  an  Old  Model  of  the  Hiker  Engine,  show- 
ing  gravity  oil  feed  and  splash  lubrication.  Oil  flows  from  the  oil  tank  to  the 
crank  case,  and  is  splashed  to  the  piston  sweep  by  the  end  of  the  connecting  rod. 
Excess  is  caught  in  the  peripheral  groove  at  the  end  of  the  piston  sweep  and 
returned  to  the  crank  case. 

principal  parts  which  it  is  particularly  necessary  to  keep  thor- 
oughly oiled  are  the  cylinder  pistons,  the  bearings  of  the  crank 
shafts  and  fly-wheels,  the  differential  gear  drum  and  the  change 
speed  gearing. 

Since  on  most  well-built  motors  and  carriages  the  moving  parts 


414  SELF-PROPELLED    VEHICLES. 

are  supplied  with  lubricating  oil  by  means  of  sight  feed  oil  cups, 
of  familiar  design,  it  is  necessary  to  do  no  more  than  to  see  that 
the  required  level  of  oil  is  always  maintained.  As  specified  by 
many  motor  carriage  authorities,  it  is  desirable  to  thoroughly  ex- 
amine and  replenish  the  oil  supply  in  the  adjustable  feed  cups 
at  the  end  of  about  every  thirty  miles  of  run.  Another  con- 
sideration of  importance  in  this  particular  is  that  before  re- 
plenishing the  supply  of  oil  to  such  parts  as  the  crank  case  or  the 
differential  gear,  the  old  lubricant  should  be  thoroughly  evacuated 
by  means  of  the  vent  cocks  supplied  in  each  case.  The  reason 
for  this  is  that,  after  a  run  of  from  twenty  to  thirty  miles,  the 
oil  in  the  moving  parts  is  apt  to  be  largely  contaminated  with  dust 
and  other  impurities,  which  tend  to  interfere  with  its  usefulness 
as  a  lubricant. 

Oil  Pumps  and  Circulation. — With  the  use  of  high-speed 
gasoline  engines,  it  has  been  found  necessary  to  use  a  forced  cir- 
culation of  the  oil  in  order  to  completely  lubricate  the  interior  of 
the  cylinder.  The  most  usual  method  with  high-powered  multiple- 
cylinder  engines  is  to  employ  a  positively  geared  pump  to  force 
the  oil  through  adjustable  sight- feed  conduits  to  the  various  mov- 
ing parts.  Such  pumps,  operating  in  ratio  to  the  speed  of  the 
engine,  of  course  supply  lubricant  more  rapidly  as  the  number 
of  revolutions  increases,  and  slow  down  as  they  decrease.  Thus, 
a  perfect  supply  is  maintained,  as  required,  on  the  one  hand,  and 
flooding  is  prevented  on  the  other.  There  are  several  efficient 
types  of  oil  pump  on  the  market,  all  working  on  the  same  prin- 
ciple of  forcing  the  oil  to  the  moving  parts  in  such  volumes  as 
may  be  determined  by  the  adjustment  One  or  two  inventors 
have  produced  devices  of  this  kind  operated  by  compressed  air 
forcing  the  oil  out  of  a  tank,  the  degree  of  compression  being 
determined  by  the  speed  of  the  engine  operating  the  a>v  pump. 


CHAPTER  THIRTY-THREE. 
PRACTICAL  OPERATION  OF  GASOUNE  ENGINES. 

Introductory. — The  automobile  engine,  although  having 
reached  a  high  degree  of  perfection  and  made  of  the  best  mate- 
rials obtainable,  is  a  piece  of  machinery  requiring  the  same  intelli- 
gent attention  in  its  care  and  management  as  any  other  high  class 
machine,  in  order  to  obtain  the  best  results  in  its  operation. 


0*10.  296. — Illustrating  the  adaptation  of  a  larpre  wrench  to  a  small  nut. 
After  the  wrench  is  applied  to  the  nut  or  bolt  head,  in  the  ordinary 
way  with  one  hand,  and  before  beginning  to  turn  it,  the  wrench  jaw 
is  packed  with  the  blade  of  a  screwdriver,  or  with  a  bit  of  metal  or 
hard  wood  held  in  the  other  hand  as  shown  in  the  cut. 

The  management  of  an  engine  embraces,  in  addition  to  the  at- 
tention given  the  engine,  the  adjustment  and  care  of  the  fuel, 
cooling  and  ignition  systems.  A  knowledge  of  ignition  and  the 
carburetter  is  the  chief  requisite  for  successful  engine  manage- 
ment. A  careful  study  of  the  chapters  devoted  to  these  subjects 
is  especially  recommended. 

415 


416  SELF-PROPELLED    VEHICLES. 

Engine  Management. — This  includes,  not  only  the  necessary 
conditions  of  operation  and  control,  which  are  simple  to  state, 
but  also  the  numerous  disorders  and  mishaps  that  may  be  en- 
countered, as  those  arising: 

1.  From  faulty  construction,  which,  however,  will  be  seldom 
experienced  with  well  made  automobiles. 

2.  From  careless  or  ignorant  handling,  such  as : 

a.  Insufficient  lubrication; 

b.  Faulty  adjustments; 

c.  Exhaustion  of  the  fuel,  current  or  jacket  water; 

d.  Racing; 

e.  Over  heating. 

3.  From  any  one  of  a  number  of  disorders  in  the  ignition  ap- 
paratus. 

4.  From  poor  gasoline,  or  faulty  adjustment  of  the  carburetter. 

5.  From  worn  or  broken  parts. 

By  far  the  greater  proportion  of  gas  engine  troubles  result 
from  some  derangement  of  the  sparking  system. 

Second  in  importance  come  troubles  with  the  fuel  mixture. 
Both  electrical  apparatus  and  carburetter  may  require  attention. 

Before  Starting  the  Engine. — There  are  three  supplies  neces- 
sary for  the  operation  of  a  gas  engine : 

1.  Gasoline; 

2.  Lubricating  oil ; 

3.  Circulating  or  cooling  water. 

In  filling  the  gasoline  tank,  the  liquid  should  always  be 
strained  to  guard  against  the  carburetter  passages  becoming 
clogged  by  any  foreign  matter  that  may  be  contained  in  the  fuel. 
A  chamois  skin  or  wire  netting  having  a  very  fine  mesh  should 
be  used  as  a  filter.  In  localities  where  gasoline  is  very  expensive, 
as  in  California,  number  one  distillate  may  be  used  which  works 
nearly  as  well  as  gasoline  except  that  it  is  necessary  to  prime  the 
carburetter  with  the  latter  in  starting  when  the  engine  is  cold. 

It  is  advisable  that  gasoline  be  tested  by  the  consumer  before 
accepting  or  using.  Compact  testing  outfits  are  to  be  had  at  small 
cost. 


ENGINE    OPERATION. 


417 


SPARK  fW9 

fMT£/l  OUTLET 

conavsnott  SPACI 

IVATfn  JACKtT 

sur  mat 


•ElHAUST  fALK  CHMBEti 
MTfff  JACKCT 

nurt  JTfft  wioe 
mm  INLET 
MU£  span/a 


CRAM  MflS 

VUT  Hire  c/in 

COIWCCTIHG  mo 


Fjo.  297. — Sectional  view  of  a  four  cycle  gas  engine,  showing  the  valve 
gear  and  other  working  parts.  Both  inlet  and  exhaust  valves  are 
mechanically  operated.  The  location  of  the  valves  diametrically 
opposite  each  other,  requires  a  separate  cam  shaft  for  each.  These 
cam  shafts  are  geared  to  the  engine  crank  shaft  and  they  make 
one  revolution  to  every  two  of  the  engine.  When  the  inlet  valve 
Is  operated  by  a  spring  and  the  engine  suction,  only  one  cam  shaft  is 
necessary  as  illustrated  in  fig.  313. 


418 


SELF-PROPELLED    VEHICLES. 


After  filling  the  tank,  the  filler  cap  should  be  replaced  and  care 
taken  that  the  small  hole  in  the  centre  of  the  cap  is  open  so  that 
air  may  be  admitted  as  the  fuel  is  used,  and  thus  prevent  the 
pressure  within  the  tank  becoming  less  than  that  of  the  atmos- 
phere. 

The  valve  on  the  fuel  supply  pipe  should  now  be  opened  and 
after  sufficient  time  has  elapsed  for  the  float  chamber  of  the  car- 
buretter to  fill,  it  should  be  noted  that  the  float  pin  is  up. 


When  the  float  pin  is  up  it  indicates  that  the  float  chamber  has  received 
a  supply  of  gasoline  from  the  tank.  If  the  pin  remain  down,  there  is  some 
obstruction  in  the  supply  pipe  preventing  the  flow  of  the  liquid  to  the 
carburetter. 


Exhaust 


PIG.  298. — Showing1  usual  location  of  tank  and  exhaust  pipe.  The  latter 
passes  under  the  tank  and  the  construction  should  be  such  that  the 
pipe  is  well  secured  to  prevent  whip-sawing. 

Next,  the  radiator  at  the  front  of  the  car  should  be  filled  with 
clean  water.  As  with  the  fuel,  the  same  care  should  be  taken  with 
the  water,  to  see  that  it  is  free  from  any  foreign  matter  as  the 
restricted  passages  of  the  radiator  might  become  clogged  and  its 
efficiency  impaired. 

After  filling  the  radiator,  it  is  advisable  to  turn  the  engine  over 
several  times  to  allow  the  water  to  circulate  through  the  cooling 
system  and  fill  any  air  pockets  that  may  have  formed.  This  will 


ENGINE    OPERATION. 


419 


be  indicated  by  a  lowering  of  the  water  level  in  the  radiator.  In 
which  case  more  water  should  be  added.  If  the  car  be  driven  in 
winter,  a  good  non-freezing  solution  should  be  used. 

It  is  an  excellent  plan  that  both  the  gasoline  and  water  tanks  be 
tested  on  each  occasion  of  preparing  for  a  run.  Some  automo- 
biles have  glass  gauge  tubes  fixed  to  the  fuel  and  water  tanks,  so 


FIG.  299. — The  Locomobile  cooling  system.  The  cooling  water  is  circu- 
lated by  a  centrifugal  pump  -which  draws  the  water  from  the  bot- 
tom of  the  radiator  and  forces  it  upward  to  the  cylinders,  whence 
through  vertical  stand  pipes  it  is  carried  clear  to  the  bottom  of  the 
water  jackets,  thus  insuring  a  thorough  cooling  of  the  cylinders. 
The  hot  water  from  the  motor  then  passes  to  the  radiator,  where 
it  is  cooled  and  delivered  back  to  the  pump.  A  pressure  gauge  is 
placed  on  the  dashboard;  if  the  clutch  be  released  temporarily,  and 
the  engine  speeded  up,  the  pressure  gauge  will  register  several 
pounds,  thus  indicating  that  everything  in  the  circulating  system 
is  in  a  satisfactory  condition.  When  no  pressure  is  registered  it 
is  an  indication  that  the  gauge  is  out  of  order  or  that  the  water  sup- 
ply needs  to  be  replenished. 

that  the  level  of  the  liquids  may  be  determined  at  a  glance.  In 
others  it  is  a  simple  matter  to  test  the  level  by  inserting  a  stick 
in  the  filling  hole  and  noting  the  height  to  which  the  liquid  rises 
on  it.  This  may  be  done  with  gasoline  if  the  stick  be  withdrawn 
quickly  and  examined  before  evaporation  takes  place. 


420 


SELF-PROPELLED    VEHICLES. 


ENGINE    OPERATION.  421 

Oil  is  a  most  essential  requisite  in  the  operation  of  automobiles. 
There  are  several  methods  of  lubrication  in  general  use,  of  which 
may  be  mentioned : 

The  gravity  system,  in  which  the  lubricator  is  placed  at  a  sufficiently 
high  elevation  to  permit  the  oil  to  flow  to  the  bearings. 

The  splash  system,  in  which  a  quantity  of  oil  is  placed  in  the  crank  case 
and  maintained  at  such  a  level  that  the  ends  of  the  connecting  rods 
come  in  contact  with  the  oil  at  the  lower  part  of  their  revolution  and 
splash  it  upon  the  working  parts. 

The  pressure  system,  in  which  the  oil  is  contained  in  a  reservoir  under 
pressure  which  forces  it  to  the  various  bearings  by  connecting  the  reser- 
voir to  the  exhaust  by  a  small  pipe  or  by  utilizing  the  pressure  from  an 
enclosed  crank  case. 

The  positive  system,  in  which  a  pump  geared  to  the  engine  forces  a 
certain  amount  of  oil  through  the  feeds  at  each  stroke  of  the  plunger. 

Before  starting  the  engine,  all  the  other  working  parts  requir- 
ing lubrication  should  receive  attention  and  in  general,  it  is  well1 
to  adhere  to  the  manufacturer's  instructions  in  the  performance 
of  this  task.  The  transmission  case,  the  steering  gear  case  and 
the  rear  axle  housing  may  be  supplied  with  a  mixture  of  oil  and 
grease  which  insures  lubrication  for  the  gears  and  bearings.  The 
transmission  case  requires  under  ordinary  conditions,  gear  grease 
mixed  with  heavy  oil  about  once  a  month.  The  bevel  gears,  dif- 
ferential, steering  gear  and  wheels  are  sometimes  packed  with 
a  non-fluid  lubricant  sufficient  for  a  season's  use. 

The  quality  of  lubricating  oil  required  for  gas  engine  cylinders 
is  quite  different  from  that  used  for  steam  engines.  Owing  to 
the  high  cylinder  temperatures  a  gas  engine  must  have  an  oil  pos- 
sessing a  high  fire  test.  As  the  average  cylinder  temperatures 
may  be  said  to  be  from  300  to  400  degrees  Fahrenheit,  an  oil 
should  be  used  having  a  fire  test  higher  than  the  latter  figure; 
the  flashing  point  should  not  be  less  than  300  degrees.  Air  cooled 
engines,  being  hotter  under  working  conditions  than  water  cooled, 
require  a  lubricant  capable  of  withstanding  higher  temperatures 
than  that  required  by  the  latter.  The  most  desirable  oils  are  those 
free  as  possible  from  carbon.  Clear  oils  have  less  suspended  car- 
bon than  dark  oils. 

In  addition  to  the  attention  required  in  supplying  gasoline, 
water  and  oil  as  just  described,  it  is  necessary  before  starting  the 
engine  to  make  sure : 


422 


SELF-PROPELLED    VEHICLES. 


1.  That  the  brake  is  set  which  releases  the  clutch  so  that  the 
car  cannot  start  until  desired ; 

2.  That  all  parts  of  the  lubricating  system  are  in  working-  or- 
der, all  connections  opened,  and  the  supply  of  oil  sufficient ; 

3.  That  the  ignition  circuit  is  closed,  which  involves  examina- 
tion of  all  switches,  to  insure  certainty  that  they  are  on  the 
"closed"  point ; 

4.  That  the  carburetter  control  levers  be  placed  in  position   for 
ensuring  the  richest  mixture  under  operating  conditions,  in  order 


FIG.  301. — The  Adams-Farwel)  engine.  This  Is  not  a  rotary  but  a  revolv- 
ing engine.  It  operates  upon  the  four  cycle  principle,  except  that  the 
cylinders  are  allowed  to  revolve  instead  of  the  crank  shaft  which  is 
keyed  to  a  stationary  base.  The  force  of  the  explosion,  being  con- 
fined between  two  objects,  moves  the  one  offering  the  least  resist- 
ance. A  is  the  stationary  crank  pin  and  B  the  shaft  centre  around 
which  the  cylinders  revolve.  The  engine  is  air  cooled  and  requires 
no  fan  on  account  of  the  motion  of  the  cylinders. 

that,  even  with  the  low  suction  at  starting,  sufficient  power  may  be 
obtained  for  a  good  headway ; 

A  rich  mixture  may  occasionally  fafl  to  ignite  at  starting,  but  a  weak 
mixture  is  more  often  at  fault. 

5.  That  the  lever  on  the  spark  control  quadrant  stands  at  the 
extreme  "back"  position,  retarding  the  spark  to  the  limit. 

To  neglect  this  may  cause  "back  kick"  at  cranking,  and  possi- 
bly result  in  serious  injury  to  the  operator. 


ENGINE,    OPERATION.  423 

6.  That  the  throttle  be  opened  partly.  It  should  not  be  opened 
any  further  than  is  necessary,  so  that  the  engine  will  not  race 
after  cranking. 

Preparing  to  Start  in  Winter  Time. — Sometimes  gas  engines 
work  indifferently  in  cold  weather;  a  low  temperature  interferes 
with  effective  engine  performance  in  several  ways : 

1.  It  renders  difficult  a  rapid  vaporization  of  the  fuel. 

2.  It  causes  the  lubricating  oil  to  thicken,  and  in  some  cases 
to  become  gummy. 

3.  It  causes  freezing  of  the  jacket  water,  unless  precautions  be 
taken  to  prevent  it. 


FIG.  302. — Steering  Wheel  and  Control  Levers  of  the  Vinot  Motor  Car- 
riage. The  throttle  and  spark  levers  work  on  opposite  arcs  of  the 
ring.  Both  turn  clockwise  for  high  sneed  adjustments,  and  counter 
clockwise  for  low  speeds. 

Carburetting  in  Cold  Weather. — The  uncertainty  regarding 
good  vaporization  is  the  principal  source  of  failure  to  operate  in 
winter  time,  and  furnishes  an  argument  in  favor  of  jacketing,  or 
heating  the  air  supply.  It  is  obviously  impracticable,  to  heat  the 
ordinary  variety  of  sprayer,  except  by  arranging  the  air  feed  pipe 
to  run  over  or  around  the  muffler,  which  would  doubtless  assist 
matters  considerably  after  the  engine  is  started.  The  hot  exhaust 
gases  are  used  by  some  designers  for  heating  the  mixing  cham- 
ber, and  the  circulating  water  by  others. 


424 


SELF-PROPELLED   VEHICLES. 


Sticking  from  Gummed  Oil. — In  cold  weather,  or  after  the 
engine  has  been  inactive  for  a  considerable  period,  the  oil  in  the 
cylinder  is  likely  to  be  thickened,  with  the  result  that  it  is  un- 
usually difficult  to  turn  the  crank.  If  a  few  turns  with  the  elec- 
tric switch  open,  do  not  suffice  to  loosen  the  adhesion  by  fric- 
tion, the  result  may  be  accomplished  by  squirting  a  small  quantity 
of  gasoline  over  the  piston  with  a  syringe. 

Freezing  of  the  Jacket  Water. — Nearly  the  most  fatal  form 

of  carelessness  in  the  management  of  a  gasoline  engine  is  to  allow 
the  cooling  water  to  freeze  in  the  jackets.    A  frozen  water  jacket 


FIG.  303. — Method  of  grinding  valves  in  horizontal  cylinders.  A  block  of 
steel  B  is  held  against  the  head  of  the  valve  V  and  the  latter  rotated 
on  its  seat  by  means  of  a  screwdriver  blade  8  inserted  in  the  slot 
in  the  stem,  the  face  having  been  previously  trued  by  a  truing  tool. 
In  cases  where  the  stem  of  the  valve  has  no  slot,  a  pair  of  gas  pliers 
can  be  used  to  grip  it,  being  careful  in  so  doing,  not  to  mutilate  the 
threads  thereon. 

generally  bursts,  without  however,  doing  certain  injury  to  the 
arched  walls  of  the  cylinder.  The  engine  may  be  started,  there- 
fore, but  soon  heats  np,  the  jacket  water  leaking  out  through  the 
breaks. 

Precautions  to  Prevent  Freezing. — In  cold  weather  a  careful 

automobile  driver  will  drain  all  water  from  the  jackets  and  cir- 
culating system  by  opening  all  pet  cocks  on  the  cylinder  jacket, 
the  pump  and  feed  pipes  and  the  radiator.  After  the  water  has 
entirely  run  out,  the  jackets  and  pipes  may  be  dried  by  allowing 
the  engine  to  run  for  not  over  a  minute,  thus  vaporizing  and 
expelling  all  remaining  moisture. 


ENGINE   OPERATION. 


425 


Non-freezing  Jacket  Solutions. — When  a  motor  vehicle  is  to 
be  run  in  winter  weather,  particularly  if  it  is  to  be  left  standing 
with  the  engine  not  operating,  some  kind  of  non-freezing  water 
solution  should  be  used  or  the  circulating  system  thoroughly 
drained.  Such  a  solution  is  one  that  lowers  the  freezing  point  of 


FIG.  304. — Method  of  using  a  screwdriver  for  valve  grinding.  A  handful 
of  waste  or  a  cloth  is  put  in  the  valve  port  to  protect  the  cylin- 
der, and  the  valve  face  coated  with  a  paste  of  fine  emery  powder  and 
oil  and  put  in  place.  The  handle  of  the  screwdriver  is  now  held  be- 
tween the  palms  of  the  hands,  as  in  the  sketch,  and  a  series  of  oscil- 
lations through  a  small  arc  given  to  the  valve  by  moving  the  palms 
in  opposite  directions.  After  about  thirty  of  these  oscillations  have 
been  given,  the  valve  is  lifted  from  its  seat,  given  a  half  turn,  and 
reseated  for  further  grinding  in  the  same  manner.  This  operation 
should  be  continued,  with  occasional  additions  of  oil  and  emery, 
until  the  valve  face  and  the  seat  appear  to  be  bright  for  their  full 
width  around  the  circle. 

FIG.  305. — Method  of  grinding  valve  with  a  drill  stock.  A  screwdriver  bit 
is  inserted  in  the  chuck  and  the  operation  conducted  as  in  the  case 
where  a  screwdriver  is  used.  Owing  to  the  multiplication  between 
the  driving  and  the  driven  bevels,  the  crank  should  be  rocked 
through  a  small  arc,  instead  of  being  rotated.  The  spring  A  is 
fitted  within  the  valve  chamber  to  unseat  the  valve  when  it  is  de- 
sired to  examine  it  or  when  a  half  turn  is  to  be  given  the  valve  on 
its  seat. 


426  SELF-PROPELLED  VEHICLES. 

the  water,  allowing  it  to  remain  liquid  below  32°?.    (o°C.). 
There  are  several  such  in  use,  all  recommended  by  authorities : 

1.  A  solution  of  water  and  glycerine:  water  70%  by  weight; 
glycerine  2$%  to  30%  by  weight;  sodium  carbonate  or  "washing 
soda,"  2%  by  weight 

The  glycerine  is  liable  to  congeal  at  very  low  temperatures,  but  this 
tendency  is  largely  neutralized  by  the  presence  of  the  soda.  With  this 
solution  the  contents  of  the  jacket  and  radiator  had  best  be  drawn  off, 
and  renewed  at  least  once  a  month. 

2.  A  solution  of  water  and  calcium  chloride,  in  proportions  of 
10  Ibs.  calcium  chloride,  dissolved  in  a  pailful  of  boiling  water, 
forming  a  saturated  solution. 

Allow  the  mixture  to  boil,  and  then  to  settle.  Test  with  litmus  paper  for 
acid,  which  may  be  neutralized  with  quicklime.  Test  occasionally  for  acid 
formed  by  heat 

Before  pouring  this  solution  into  the  tank,  it  should  be  carefully  strained 
through  a  fine  cloth,  to  remove  all  sediment. 

Only  the  chemically  pure  calcium  chloride,  sold  by  responsible  chemists, 
should  be  used  for  this  solution,  and  one  should  carefully  avoid  using  the 
so-called  "chloride  of  lime,"  commonly  known  as  calcium  hypochlorite. 

3.  A  solution  of  equal  parts  by  weight  of  water  and  wood 
alcohol. 

4.  A  solution  of  two  parts  wood  alcohol,  I  part  glycerine,  I  part 
water,  is  also  recommended  by  Roberts. 

Draining  the  Jackets. — Although  any  one  of  the  solutions 
given  above  prevent  freezing  of  the  jacket  water,  many  users 
find  it  more  satisfactory  to  drain  the  jackets  through  the  pet  cock 
on  the  radiator,  when  the  car  is  to  stand  over  night,  and  refill 
before  the  next  start  of  the  motor.  This  practice  is  preferable 
because  the  solutions  are  troublesome  and  dirty,  and  at  best,  do 
not  cool  as  well  as  pure  water. 

Spark  and  Throttle  Adjustments  before  Starting. — On  ac- 
count of  the  slow  speed  at  which  the  engine  is  turned  over  in 
cranking,  it  is  necessary  that  the  throttle  have  a  considerable  de- 
gree of  opening  and  that  the  spark  be  fully  retarded  because  of : 

1.  The  weak  suction  of  the  piston  at  slow  speed; 

2.  The  need  of  ensuring  a  mixture  that  will  ignite  under  such 
conditions ; 


ENGINE    OPERATION. 


427 


3.  The  danger  of  bodily  injury  from  a  "back  kick"  of  the  en- 
gine, which  is  liable  to  occur  with  an  early  spark  at  slow  speeds, 
as  will  be  described  later. 

Cranking. — It  may  be  well  to  repeat  here  that  the  operator 
should  never  attempt  to  crank  an  engine  until : 

1.  The  brake  is  set,  releasing  the  clutch; 

2.  The  transmission  lever  is  placed  in  the  neutral  position; 

3.  The  spark  fully  retarded. 

The  neglect  of  this  caution  may  be  followed  by  serious  conse- 
quences. 


Right  Way 


Wrong  Way 


PIGS.  306  and  307. — Illustrating  right  and  wrong  methods  of  cranking  an 
engine.  As  ordinarily  practiced,  the  hand  is  so  placed  that  the 
thumb  and  fingers  encircle  it.  Such  a  method  is  decidedly  unsafe 
should  the  operator  press  down  on  the  crank  and  a  back  fire  occur. 
The  correct  method,  is  to  place  the  thumb  on  the  same  side  of  the 
handle  that  the  fingers,  are  placed  so  that  the  handle  is  not  entirely 
encircled,  allowing  the  handle  to  slip  out  of  the  grasp  when  it  is 
being  pressed  down,  and  permitting  the  fingers  to  release  the  handle 
if  it  is  being  pulled  up,  at  the  time  of  back  fire. 

In  cranking,  the  operator  faces  the  car  and  grasps  the  crank 
handle  with  the  four  fingers  of  the  right  hand,  allowing  the  thumb 
to  lie  along  the  handle.  The  crank  is  now  raised  to  its  highest 
position,  pressed  in  toward  the  car  and  turned  downward. 

If,  at  the  beginning  of  this  movement,  it  turn  hard  indicating 
Compression,  the  operator  should  allow  the  crank  to  spring  out  of 


428 


SELF-PROPELLED    VEHICLES. 


engagement  with  the  shaft  and  revolve  backward  far  enough  so 
that  he  will  pull  up  against  compression. 

An  engine  should  never  be  cranked  downward  against  com- 
pression, for  in  case  the  spark  has  not  been  fully  retarded,  the 
pressure  of  the  early  explosion  may  overcome  the  momentum  of 
the  fly  wheel  and  drive  the  handle  violently  backward,  resulting 
in  at  least  a  seriously  sprained  wrist. 

It  is  well  for  the  novice  to  first  make  two  or  three  turns  with 
the  switch  off,  then  a  final  turn  with  the  switch  on  when  the  en- 
gine should  start. 


FIG.  308. — Steering  Wheel  and  Attachments  of  the  Pope-Toledo  Carriage. 
A  is  the  wheel  rim:  B.  a  spoke  or  arm  of  the  three-armed  spider; 
C,  sector  for  sliding  arms,  D  and  E;  D,  throttling  arm  and  handle; 
E,  spark  regulating  handle.  The  throttle  is  opened  by  moving  the 
handle  clockwise  around  the  sector;  .the  spark  is  advanced  by  mov- 
ing its  handle  In  the  same  direction. 

Another  method  for  the  beginner,  consists  in  turning  the  handle 
till  he  is  sure  he  is  pulling  upward  against  compression,  then  re- 
lieving the  compression  somewhat  by  partly  opening  and  closing 
the  relief  cock,  after  which  the  turn  is  quickly  completed. 

Some  engines  are  provided  with  an  exhaust  valve  lifter,  which 
is  used  to  relieve  compression  during  the  first  few  turns  in  crank- 
ing. 


ENGINE    OPERATION. 


429 


If  the  compression  in  the  cylinders  be  good,  a  multi-cylinder 
engine  can  usually  be  started  as  follows : 

The  primary  switch  is  first  opened  and  the  engine  turned  over  a  few 
times  until  a  fresh  charge  is  obtained  in  each  cylinder.  The  operator 
then  mounts  the  seat  and  after  closing  the  switch,  the  spark  lever  is 
suddenly  pushed  forward  as  far  as  it  will  go.  This  operation  will  usually 
cause  a  spark  in  one  of  the  cylinders  and  start  the  engine. 

Misfiring  During  Operation. — Occasionally,  the  missing  of 
one  or  more  of  the  cylinders  will  be  noticed  during  the  operation 
of  the  engine.  This  trouble  may  be  recognized  by  irregularity 
of  motion,  gradual  slowing  down,  and,  generally,  by  after  firing, 
or  explosions  in  the  muffler. 


|ExteiJngKxhaur.to          o         p p 


FIG.  309. — A  simple  form  of  muffler,  as  used  on  many  cars  and  which  gives 
good  satisfaction  when  well  designed.  It  consists  of  a  cylinder  and 
a  pipe  so  contrived  that  the  pipe,  which  is  drilled  full  of  small  holes, 
will  admit  the  exhaust  at  high  pressure,  and  as  it  is  required  to  pass 
through  a  large  number  of  small  holes,  it  is  split  up  and  then  ex- 
panded. The  gas  passes  to  the  atmosphere  in  an  even  flow,  at  a 
pressure  slightly  above  that  of  the  atmosphere.  This  type  of  muffler 
is  fairly  efficient  when  well  designed. 

If  the  trouble  cannot  be  located  in  one  of  the  cylinders  the 
inference  holds:  either  that  there  is  some  general  derangement 
of  the  ignition  circuit,  or  that  the  fuel  mixture  is  not  right. 

Back  Firing  and  Back  Kick. — This  is  a  form  of  disordered 
action,  sometimes  encountered  on  starting  the  engine,  and  most 
often  due  to  non-observance  of  necessary  rules,  as  already  laid 
down,  for  adjusting  the  engine  and  auxiliary  parts.  In  back  fir- 
ing the  ignition  of  the  charge  takes  place  at  such  a  point  in  the 
cycle  that  the  motion  of  the  engine  is  reversed. 

If  back  firing  occur  while  the  operator  is  holding  the  crank, 
it  produces  a  back  kick,  which  is  liable  to  dislocate  his  shoulder 
unless  the  crank  throws  off  automatically. 


430 


SELF-PROPELLED    VEHICLES. 


The  term  back  firing  is  also  applied  to  an  explosion  occurring 
during  or  at  the  end  of  the  inlet  stroke,  when  the  gas  in  the 
carburetter  mixing  chamber  is  ignited.  This  is  due  generally  to 
a  loose  or  defective  inlet  valve,  a  pitted  inlet  valve  seat,  smolder- 
ing carbon  residue  in  the  cylinder  space,  or  a  spark  due  to  a  dis- 
arranged ignition  circuit.  The  logical  presumption  is  that  the 
inlet  valve  needs  grinding  in  its  seat,  in  the  same  manner  as  is 
subsequently  explained  in  connection  with  the  exhaust  valve. 

Back  firing,  or  ignition  at  the  wrong  point  in  the  cycle,  with 
reversed  piston  movement,  must  be  carefully  distinguished  from 
after  firing,  or  explosion  in  the  muffler  or  exhaust  pipe.  Occa- 
sionally the  same  term  is  erroneously  applied  to  both  mishaps. 


t 


Exhaust  Enters 


High  Eressure 

Chamber. 
Small  holcsf— 


'^^!^^^^^^^i^f^^'^^ff^^-'''A^y'jf'-  ^^^-^^  •^^'^'^^^ 


Low  Pressure 
Chamber. 


m 

Exhaust  Exit > 


FIG.  310. — Simplex  type  of  muffler,  showing-  three  chambers — a  high  pres- 
sure, intermediate,  and  low  pressure  chamber,  so  contrived  that  the 
pressure  is  reduced  almost  to  zero  before  the  exhaust  makes  its  exit 
to  the  atmosphere.  The  volume  of  the  high  pressure  chamber  is 
equal  to  that  of  one  of  the  engine  cylinders;  the  intermediate  cham- 
ber has  twice  the  volume,  and  the  low  pressure  chamber  three  times 
the  volume  of  the  engine  cylinder. 

Causes  of  Back  Firing. — Back  firing,  or  pre-ignition,  may 
occur  under  several  conditions.  Prominent  among  these  are: 

i.  An  early  ignition,  at  or  before  the  backward  dead  centre  of 
the  crank,  before  the  cycle  is  established,  as  in  the  act  of  cranking 
the  engine  for  a  start.  The  result  is  then  a  back  kick,  as  already 
explained.  This  can  only  emphasize  the  necessity  of  retarding 
the  spark  at  starting,  so  that  it  will  not  occur  until  the  piston  is 
at,  or  very  near  the  dead  centre. 


ENGINE    OPERATION.  431 

2.  Over  heating  of  the  cylinder  walls,  due  to  insufficient  heat 
radiation  (in  an  air  cooled  engine)  or  too  little  jacket  water  (in 
a  water  cooled  engine).    This  should  emphasize  the  necessity 
of  keeping  the  water  supply  sufficient  for  all  needs,  and  of  assur- 
ing the  perfect  operation  of  the  circulation  system,  pump,  radiator* 
etc.,  before  starting  the  engine. 

3.  Soot  deposits  within  the  combustion  space,  due  to  carboniza- 
tion of  excess  oil,  etc.     Such  deposits  will  readily  ignite  and 
smolder,  and  will  thus  furnish  an  almost  certain  source  of  ignition, 
during  the  compression  stroke. 

Spark  and  Throttle  Adjustments  after  Starting. — When 
the  engine  has  speeded  up,  the  adjustments  must  be  changed : 

1.  The  spark  must  be  advanced. 

2.  The  throttle  opening  must  be  reduced. 

If  there  be  a  mechanical  governor  on  the  engine,  the  throttle 
will  shut  down  automatically,  as  the  engine  speeds  up.  • 

On  account  of  the  spark  and  throttle  adjustments  necessary  in 
cranking,  the  engine  when  started  will  begin  to  race  unless  it  be 
fitted  with  a  governor,  hence,  the  operator  should  immediately 
reduce  the  throttle  opening  and  advance  the  spark  so  the  engine 
will  run  at  its  slowest  speed  while  the  car  is  standing.  The  throt- 
tle lever  should  be  pushed  all  the  way  back ;  this  does  not  close 
the  valve  entirely  but  leaves  sufficient  opening  to  supply  the  mini- 
mum charge  to  the  engine. 

Failure  to  Start. — Refusal  of  the  engine  to  take  up  the  cycle, 
even  after  prolonged  cranking,  is  a  familiar  experience  in  automo- 
bile operation.  Unless  some  accident  has  occurred,  or  a  very 
unusual  strain  has  been  thrown  upon  the  working  parts,  the  in- 
ference is  that  some  element  of  the  rather  complicated  group  of 
mechanisms  is  out  of  adjustment,  and  in  most  cases  the  failure 
to  start  is  due  to  some  faulty  adjustment  or  defect  of  the  carburet- 
ter or  ignition  system. 

Causes  of  Failure  to  Start. — In  cranking,  it  should  be  remem- 
bered that  a  few  rapid  turns  of  the  crank  handle  will  do  more  to- 
wards starting  an  engine  than  ten  minutes  of  slow  grinding. 


432  SELF-PROPELLED   VEHICLES. 

If  an  engine  show  good  compression  and  will  not  start  after 
four  or  five  turns,  it  is  useless  to  continue.  Assuming  that  all 
the  preliminaries  to  starting  hitherto  specified  have  been  care- 
fully observed,  the  probable  causes  of  trouble  should  be  sought : 

1.  In  the  spark  plug; 

2.  In  the  secondary  wiring; 

3.  In  the  vibrator  of  the  coil; 

4.  In  the  interior  of  the  coil; 

5.  In  the  timing  device; 

6.  In  the  primary  wiring; 

7.  In  the  current  source  ^rima7  or  s.econdary  batteries- 

(magneto  or  dynamo. 

8.  In  the  carburetter. 

The  several  causes  of  failure  to  start  the  engine  as  mentioned 
above,  will  now  be  briefly  explained  in  the  order  given. 

Defective  Spark  Plugs. — The  engine  will  not  start  when: 

1.  The  plug  points  are  too  far  apart. 

2.  The  plug  is  short  circuited. 

3.  The  insulating  layer  of  porcelain  or  mica  is  broken  down. 

4.  There  is  much  fouling  between  the  plug  points. 

Fouling  may  consist  of  oil  or  soot.  Both  give  trouble  at  start- 
ing. 

Fouling  with  soot  may  generally  be  removed  with  gasoline. 
Preventives  of  fouling  are : 

1.  An  annular  space  between  the  core  insulation  and  the  outer 
shell,  producing  a  vortex,  as  is  alleged,  and  allowing  piston  suc- 
tion to  remove  deposits. 

2.  An  auxiliary  spark  gap,  which  will  generally  suffice  to  insure 
a  spark,  but  it  does  not  prevent  fouling  between  the  spark  points. 
A  temporary  gap  may  be  made  by  disconnecting  the  lead  wire 
of  the  plug  and  holding  its  end  at  a  sufficient  distance  to  allow 
a  visible  spark  to  leap  from  it  to  the  plug  core. 


ENGINE    OPERATION.  433 

If  this  prove  ineffective,  the  plug  should  be  unscrewed  and  ex- 
amined. Any  visible  fouling  may  then  be  removed  by  rubbing 
the  insulation  with  fine  sand  paper  until  the  bright  surface  of  the 
porcelain  is  visible,  taking  care  not  to  impair  the  surface. 

If  no  fouling  appear  the  plug  may  be  laid  upon  the  cylinder  or 
frame  so  that  its  case  only  is  in  contact,  and  thus  grounded,  and 
on  cranking  the  engine,  the  spark  may  be  seen  leaping  between 
the  points. 

If  a  spark  does  not  appear,  it  is  probable  that,  with  the  igni- 
tion circuit  in  working  order,  there  is  some  breakage  or  short 
circuit  in  the  body  of  the  plug.  This,  of  course,  necessitates  its 
removal  and  the  substitution  of  a  new  one.  If  a  good  spark  ap- 
pear, the  search  for  trouble  must  be  continued  to  other  parts. 

In  a  multi-cylinder  engine  a  defective  plug  may  sometimes  be 
located  by  touch,  that  is,  if  its  cylinder  has  been  missing  for  some 
time  the  metal  of  the  plug  will  be  perceptibly  cooler  than  that  of 
the  other  plug?; 

Defects  in  the  Secondary  Wiring. — The  current,  on  account 
of  defective  insulation  may  short  circuit  to  some  metallic  portion 
of  the  car  or  engine.  If  the  secondary  lead  be  disconnected  from 
the  spark  plug,  the  current  may  sometimes  be  heard  or  seen  in 
discharging. 

Misfiring:  Short  Circuits. — Very  frequently  misfiring  is  caused 
by  a  short  circuit,  which  is  to  say  a  ground,  or  an  arcing  gap  be- 
tween the  two  sides  of  the  secondary  circuit,  at  some  point  short 
of  the  plug  terminals.  This  will,  of  course,  prevent  sparking  at 
the  plug,  although,  owing  to  the  vibration  of  operation  in  the 
other  cylinders,  the  short  circuit  may  occasionally  be  interrupted 
and  the  spark  will  occur. 

Such  a  short  circuit  differs  from  an  auxiliary  spark  gap,  in 
that  the  latter  is  in  series  with  the  plug  gap,  while  the  former 
gives  a  leak  in  parallel  to  it. 

Vibrator  Failures. — There  may  be  a  defective  adjustment  of 
the  vibrator,  which  will  prevent  it  responding  to  the  strength  of 
current  in  use,  or  the  vibrator  may  be  broken  loose. 


434 


SELP-PROPBUMD  VEHICLES. 


FIG.  311. — Locomobile  low  tension  Igniter.  I  is  the  igniter,  the  upper 
end  of  the  tappet  rod  T,  is  hooked  to  the  hammer  lever  H,  and  as 
the  tappet  rod  is  given  vertical  motion  by  one  of  the  cams  on  the 
cam  shaft  C — C,  and  rises,  the  hammer  comes  in  contact  with  the 
anvil  A  and  stays  there  until  the  cam  has  reached  such  a  position 
that  the  tappet  rod  suddenly  falls,  causing  the  hammer  to  separate 
sharply  from  the  anvil  and  the  spark  to  occur,  the  action  being  as- 
sisted by  a  strong  enclosed  spring  8T  at  the  bottom  of  the  tappet 
rod.  A  spring  S  at  the  top  of  the  tappet  rod  keeps  the  electrodes 
in  contact  until  it  is  time  for  the  break  to  occur.  Knife  blade 
switches  such  as  K,  form  electrical  contact  between  an  insulated  bus- 
bar B,  B,  on  the  motor  and  anvils. 

As  will  be  evident  on  reflection  and  from  previous  explanations, 
the  spark  in  the  cylinder  does  not  occur  at  the  same  point  in  the 
piston  stroke  at  high  and  low  speeds,  nor,  ever  necessarily,  at  the 


ENGINE    OPERATION.  435 

moment  the  primary  circuit  is  made  at  the  timer.  This  is  due 
partly  to  the  vibrator  and  partly  to  the  coil.  Some  time  is  always 
required  to  saturate  the  coil,  make  the  break  and  discharge  the 
core,  producing  the  jump  spark. 

The  average  duration  of  these  operations  is  about  .005  second,  which, 
although  quite  negligible  at  low  speeds,  requires  progressive  advances  of 
the  timer  as  speed  increases.  The  movement  of  the  vibrator  also  con- 
sumes a  fraction  of  a  second,  its  speed  being  indicated  by  the  pitch  of 
its  buzz,  but  unless  the  speed  be  very  high,  the  time  for  occurrence  of  the 
spark  is  changed.  If  the  vibrator  be  leaving  the  core  at  the  moment 
of  circuit  making  at  the  contact  maker,  the  time  of  one  vibration  must 
elapse  before  the  occurrence  of  the  spark;  if  the  vibrator  be  in  contact 
at  this  moment,  the  spark  follows  almost  immediately.  These  facts  en- 
force the  desirability  of  high  speed  vibration. 

In  a  multiple  cylinder  engine  using  a  separate  coil  for  each 
cylinder,  the  vibrators  should  be  tuned  as  nearly  as  possible  to 
the  same  pitch  or  rate  of  vibration;  otherwise  the  sparks  will 
occur  at  different  points  of  the  several  respective  piston  strokes. 

In  most  cases  the  vibrator  requires  no  adjustment,  however, 
the  instructions  given  for  vibrator  adjustment  in  the  chapter  on 
ignition  may  be  supplemented  by  the  following: 

a.  When  the  adjusting,  or  back  stop  screw  is  turned  inward, 
forcing  the  vibrator  nearer  to  the  pole  of  the  core,  the  rapidity 
of  vibration  will  be  increased. 

b.  When  the  adjusting  screw  is  turned  outward,  increasing  the 
distance  between  the  vibrator  and  pole  of  the  core,  the  rate  of 
vibration  will  be  decreased. 

c.  There  are  very  definite  limits  to  the  proper  operation  of  the 
core,  at  either  loose  or  tight  adjustment. 

d.  A  fair  adjustment  for  low  speeds  may  prove  unsuitable  for 
high  speeds,  and  vice  versa. 

e.  A  fair  adjustment  for  a  strong  battery  will  probably  be  found 
unsuitable  for  a  weak  battery,  and  vice  versa.     Therefore,  the 
battery  should  receive  attention,  rather  than  the  coil  adjustment. 

f.  With  the  use  of  a  jump  spark  coil,  this  is  nearly  the  strong- 
est argument  for  a  double  battery,  controlled  by  a  two  point 
switch. 


436  SELF-PROPELLED   VEHICLES. 

If  one  cares  to  risk  experiment  with  coil  adjustments,  he  will 
soon  discover  the  range  of  efficient  action. 

As  a  general  proposition,  the  following  rules  hold  good  for 
adjustment  of  the  coil : 

1.  The  vibrator  should  vibrate  with  sufficient  rapidity  to  give 
a  distinctly  musical  sound. 

2.  Rapid  vibration,  except,  of  course,  one  that  is  excessive,  is 
more  efficient  and  better  for  the  battery  than  one  that  is  slower. 

3.  Reducing  the  rate  of  vibration  increases  the  efficiency  of  a 
weak  battery,  according  to  the  statements  of  some  authorities. 

The  truth  of  the  matter  is  that  reducing  the  rate  of  vibration  produces 
a  stronger  spark  by  permitting  the  coil  to  saturate  more  fully. 

A  constant  sounding  of  the  vibrator  indicates  a  leak  or  short 
circuit  somewhere,  and  should  be  immediately  investigated.  A 
short  circuit  is  the  quickest  means  for  exhausting  a  chemical  bat- 
tery. On  the  other  hand,  it  means  speedy  destruction  for  a 
storage  battery,  as  will  be  explained  later. 

Misfiring:  Faulty  Vibrator  Adjustment. — Among  the  causes 
which  produce  misfiring  at  high  speeds  may  be  mentioned  a 
faulty  adjustment  of  the  coil  vibrator,  giving  extremely  short 
makes  of  the  primary  circuit  and  slow  rates  of  vibration,  which 
cannot  keep  pace  to  the  requirements  of  high  engine  speeds. 

Loose  circuit  connections,  shaken  out  of  position  as  the  engine 
speeds  up,  and  weakened  batteries  are  common  causes  of  this  mis- 
hap at  high  speeds. 

Defects  in  the  Interior  of  the  Coil. — Electrical  faults  in  this 
part  of  the  ignition  system  may  be  caused  by  the  presence  of  mois- 
ture, oil  or  dirt  and  by  the  condenser  not  being  suited  to  battery. 

The  coil  generally  needs  very  little  attention.  Provided  the 
battery  be  maintained  at  an  approximately  even  efficiency,  and 
the  coil  is  carefully  protected  from  moisture,  oil  and  dirt,  there 
is  virtually  no  danger  of  electrical  derangement.  It  may  be  safely 
asserted  that  the  majority  of  cases  in  which  the  coil  is  supposed 
to  be  "worn  out,"  are  merely  examples  of  irregular  or  inefficient 


ENGINE    OPERATION. 


437 


action  of  the  condenser.  Occasionally  a  spark  discharged  from 
the  condenser  occurs  at  the  moment  of  breaking  contact  of  the 
vibrator  and  screw  back  stop  with  the  result  of  burning  the  con- 
tacts. Dirt  or  oil  between  the  vibrator  contacts  will  produce 
similar  result.  In  either  case  there  will  be  no  spark  at  the  spark 
plug.  Spark  discharges  at  the  vibrator  contacts  usually  result 
from  the  condenser  not  being  suited  to  the  battery.  When  the 
condenser  is  of  proper  size,  the  spark  will  be  very  minute. 

Nothing  will  so  rapidly  deteriorate  a  high  tension  coil  as  the 
presence  of  moisture  in  its  windings.  The  water  frequently  soaks 
through  the  insulation,  short  circuiting  the  current  and  prevent- 
ing a  spark.  A  coil,  evidently  affected  by  moisture,  can  not  be 
repaired,  except  by  experienced  workmen,  and  had  best  be  re- 
placed. 

In  purchasing-  a  coil,  it  is  necessary  to  see  that  it  is  perfectly 
suitable  for  the  type  of  battery  or  generator  in  use.  Induction 


PIG.  312. — Diagram  of  the  Essential  Parts  of  an  Induction  Coll;  B,  chem- 
ical battery;  C,  C',  condenser  terminals;  I,  laminated  iron  core;  P, 
primary  winding;  S,  secondary  winding;  H,  head  of  the  vibrator;  o, 
contact  point  of  the  back  stop  screw. 


438  SELF-PROPELLED    VEHICLES. 

coils,  like  other  electric  coils,  are  wound  for  use  with  a  certain 
definite  voltage  in  the  primary  source.  Logically,  therefore,  the 
best  effect  can  not  be  obtained  unless  the  coil  and  source  arc 
mutually  suited.  This  rule  holds  for  all  types  of  source. 

Misfiring:  Defective  Coil. — A  broken  down  coil,  or  one  in 
which  the  insulation  is  weakened,  allowing  internal  leaks  and 
sparking,  will  cause  misfiring  for  a  time,  and  will  very  soon  be 
of  no  use  whatever. 

Defects  in  the  Timing  Device. — This  portion  of  the  ignition 
apparatus  should  be  examined  occasionally  for : 

1.  Loose  screws  or    contacts. 

2.  Thick  oil  or  dirt  on  contact  surfaces. 

In  a  wipe  commutator  only  the  thinnest  and  lightest  grade  of 
oil  should  be  used  on  the  contact  surface. 

Loose  or  foul  contacts  constitute  a  fertile  source  of  ignition 
failures. 

Defects  in  the  Primary  Wiring. — The  current  in  this  circuit 
being  of  low  pressure,  its  flow  is  easily  prevented  by  loose 
and  corroded  terminals,  defective  switches,  or  breaks  of  any  kind 
in  the  continuity  of  the  wire.  Hence,  special  care  should  be  taken 
with  this  part  of  the  ignition  system,  that : 

1.  The  terminals  be  kept  clean  and  bright; 

2.  The  connections  be  firmly  made ; 

3.  The  spring  portions  of  switches  be  so  adjusted  that  they 
bear  firmly,  making  a  good  contact ; 

4.  Frequent  examination  be  made  for  partial  breaks  ; 

5.  The  insulation  be  guarded  against  breaks,  flaws  or  rubbed 
areas.     By  this  means  leaks  and  short  circuits  will  be  avoided. 

Misfiring:  Loose  Connections. — Loose  connections  of  the 
wires  at  a  binding  screw,  may  cause  misfiring ;  the  looseness  may 
be  small,  or  it  may  be  excessive,  and  the  condition  in  this  respect, 
determines  the  degree  of  interference  in  engine  operation.  Thus, 
a  loose  connection  may  allow  the  engine  to  run  from  rest  to  a 
moderately  good  speed  before  trouble  begins,  or  the  vibration  of 
operation  may  interrupt  the  contact  entirely. 


ENGINE    OPERATION.  439 

Defective  Battery. — Ignition  failures  are  often  due  to  a  weak, 
run  down,  or  polarized  battery.  Dry  cells,  when  used  as  a  source 
of  current  for  sparking,  particularly  for  extended  periods,  should 
be  arranged  in  series  in  two  or  more  separate  batteries,  with 
switches  that  may  cut  all  out  of  circuit,  except  the  one  in  use  as 
current  supply.  The  reason  for  this  is  that  such  cells  are  subject 
to  deterioration  in  use,  and  a  new  battery  should  always  be  at 
hand.  Deterioration  may  result: 

1.  From  extensive  use,  after  which  the  cell  becomes  exhausted 
through  consumption  of  the  zinc  element,  or  the  electrolyte. 

2.  From  short  circuits  long  continued,  which  cause  the  cell  to 
run  out  of  current  more  rapidly  than  otherwise.    A  temporary 
short  circuit  will  not  injure  a  dry  cell  as  seriously  as  it  will  some 
other  types  of  source.    Generally,  it  will  polarize  it  more  quickly. 
A  season  on  open  circuit  will  find  it  still  serviceable. 

3.  From  neglect  to  open  the  switch  or  the  primary  circuit,  on 
stopping  the  engine.     If,  then,  there  be  a  leak,  or  the  timer  rotor 
be  in  engagement  with  one  of  the  contacts,  the  current  will  rapidly 
run  to  waste. 

Dry  cells,  so-called,  are  all  of  the  "open  circuit"  variety.  That  is  to  say, 
the  generation  of  current  produces  the  condition  known  as  "polarization," 
or  the  collection  of  hydrogen  on  the  electrode  attached  to  the  positive 
lead  wire.  This  condition  may  be  remedied,  the  cell  may  be  "depolarized," 
only  by  leaving  it  for  a  period  on  open  circuit,  or  disconnected. 

A  polarized  cell  will  show  a  low  current  register  on  the  ammeter,  but 
may  be  restored  more  or  less  after  resting. 

The  theory  and  management  of  storage  cells  are  set  forth  in  another 
chapter.  Storage  cells  used  on  sparking  circuits  are  often  charged  by  the 
surplus  current  of  the  sparking  dynamo.  "When  no  dynamo  is  used,  they 
are  charged  by  special  attachments  to  electric  feed  mains,  or  by  a  battery 
of  wet  cells  of  proper  voltage. 

In  order  that  storage  cells  should  continue  of  service  in  the 
sparking  circuit  of  a  gasoline  engine,  it  is  necessary  to  constantly 
observe  the  following  rules : 

1.  Each  cell  should  register  at  full  charge  about  2.5  volts  and 
should  never  be  used  after  the  voltmeter  falls  to  1.75. 

2.  If  short  circuited  at  any  time,  the  cell  should  be  immediately 
disconnected  and  recharged,  as  elsewhere  specified.     Short  cir- 
cuiting is  one  of  the  most  fatal  mishaps  that  can  overtake  a 
storage  cell. 


440  SELF-PROPELLED   VEHICLES. 

Misfiring:  Weak  Battery. — When  the  current  supply  is  re- 
duced, as  by  a  weak  battery,  it  may  prevent  sparking  between  the 
plug  points,  and  can  be  remedied  in  no  better  fashion — provided 
no  extra  battery  be  at  hand — than  by  reducing  the  gap  between 
the  points.  As  a  consequence,  a  weak  battery  is  a  frequent  cause 
of  misfiring. 

Misfiring  due  to  a  weak  battery  may  be  diagnosed  by  the  occa- 
sional apparent  violence  of  the  explosions,  on  account  of  frequent 
misses.  A  weak  battery  will  cause  misfiring  most  conspicuously 
when  the  engine  has  been  run  up  nearly  to  full  speed,  and  then 
suddenly  drops,  owing  to  irregular  ignitions.  The  reason  is,  ob- 
viously, that  the  weak  battery  cannot  supply  good  fat  sparks  at  a 
rate  commensurate  with  the  requirements  of  rapid  operation. 
With  a  reduced  spark  gap  and  a  slow  speed,  it  may  be  able  to 
cause  operation  for  a  limited  period. 

•          • 

These  principles  apply,  of  course,  to  chemical  batteries.  When  the  cur- 
rent is  obtained  from  a  magneto  or  dynamo,  the  trouble — if  traced  to  the 
source — is  probably  due  to  loose  or  worn  brushes,  a  glazed  commutator,  or 
a  short  circuit  somewhere  in  the  armature,  or  around  the  brush  holders. 

Defective  Generator. — As  a  rule,  troubles  with  a  mechanical 
generator  are  liable  to  arise  from  glazing  or  lack  of  adjustment 
of  the  brushes  and  commutator.  Next  to  this,  the  oil  feed  or 
bearings  should  be  carefully  watched  and  supplied,  and  the  cut- 
out governor,  if  one  be  attached,  should  be  occasionally  examined, 
to  be  sure  that  it  is  in  perfect  working  order. 

Glazing. — A  troublesome  condition  that  occasionally  appears 
in  small  dynamos  is  a  glaze  on  the  commutator  or  contact  sur- 
faces of  the  brushes.  This  may  be  removed  from  the  brushes  by 
wrapping  a  very  fine  sandpaper,  sand  side  up,  around  the  commu- 
tator and  rotating  the  spindle,  so  that  the  brush  ends  are  thor- 
oughly scoured.  It  may  be  removed  from  the  commutator  by 
rubbing  the  surface  with  the  finest  grade  of  sandpaper.  .  Emery 
paper  should  never  be  used  for  this  purpose,  since  emery,  being 
carbon,  is  a  conductor,  and  its  presence  between  the  segments  of 
the  commutator  is  liable  to  interfere  with  the  insulation.  It  also 
causes  rapid  wear. 


ENGINH    OPERATION. 


441 


Faulty  Action  of  Carburetter. — The  several  paragraphs  pre- 
ceding have  been  devoted  entirely  to  the  ignition  system  which 
is  the  source  of  most  failures  in  starting  the  engine;  second  in 
importance,  in  this  respect,  is  the  carburetter.  Success  in  start- 
ing and  running  the  engine  depends,  to  a  considerable  degree, 
upon  its  proper  adjustment  and  control  so  that  it  will  furnish  a 
mixture  of  the  right  proportions  to  meet  varying  demands. 


FIG.  313. — Illustrating  the  operation  of  a  four  cycle  engine  valve  gear. 
The  figure  shows  a  spring  actuated  inlet  valve  M  and  a  mechanically 
operated  exhaust  valve  H.  The  latter  is  opened  when  the  cam  E  re- 
volves and  raises  against  the  roller  G,  which  is  on  the  bottom  of  the 
lifter  rod  F.  The  rod  F  extends  upward  and  rests  against  the  bot- 
tom of  the  stem  of  the  valve  H,  although  between  the  two  or  at  their 
point  of  contact  are  nut  and  locknut  L  for  lengthening  or  shorten- 
ing the  lifter  F,  and  so  to  vary  the  time  of  opening  or  closing  of  the 
valve.  The  spring  K  is  compressed  or  squeezed  together  when  the 
valve  is  opened  and  immediately  the  cam  B  travels  around  and  al- 
lows the  roller  G  to  fall;  this  spring  exerts  its  pressure  and  closes 
the  valve.  The  intake  valve  M  is  automatically  opened  by  the  suc- 
tion of  the  engine. 


442  SELF-PROPELLED   VEHICLES. 

Defective  Fuel  Mixture. — It  frequently  happens  that  too  rich 
a  mixture  will  not  ignite  readily  on  cranking  and  as  a  consequence, 
the  engine  will  not  start.  It  is  necessary,  then,  to  reduce  the  mix- 
ture, allowing  more  air  to  enter  the  mixing  chamber. 

If  the  engine  start  with  a  rich  mixture,  the  result  is  liable  to 
be  seen  in  a  heavy  and  ill  smelling  smoke  from  the  muffler.  The 
color  of  this  smoke  will  determine  the  nature  of  the  trouble. 

Dark  colored  dense  smoke  indicates  an  excess  of  gasoline  in 
the  mixture,  and  may  result  from  one  of  the  following  conditions : 

1.  Imperfect  combustion. 

2.  Defective  ignition. 

3.  Either  excessive  or  defective  lubrication. 

4.  Overheating  and  consequent  flashing  of  the  lubricating  oil 

5.  A  leaky  piston. 

The  two  most  usual  causes  of  dark  smoky  exhaust,  however 
are: 

1.  Defective  carburetter  action,  due  probably  to  grit  under  th» 
inlet  needle  valve,  or  else  to  some  derangement  of  the  parts. 

2.  An  over  rich  mixture,  which  ignites  imperfectly. 

White  dense  smoke  indicates  an  excess  of  oil  or  a  resulting 
deposit  of  carbon  soot  in  the  cylinder,  or  a  poor  oil. 

Thin  blue,  or  nearly  invisible  smoke  indicates  a  normal  mixture 
and  good  ignition. 

An  unpleasant  odor  in  the  exhaust  is  frequently  mentioned  as 
the  one  necessary  evil  of  motor  carriage  operation.  It  is  certainly 
nothing  of  the  sort,  and  most  often  indicates  poor  lubricating  oil 
or  too  rich  a  mixture,  which  involves  wasteful  use  of  fuel.  A 
good  mixtrue,  perfectly  ignited,  in  a  cylinder  lubricated  with  high 
test  oil,  should  have  no  very  bad  odor. 

Bad  odors  and  smoke  at  starting  are  frequently  produced  by 
chemical  conditions  other  than  a  poor  oil  or  an  over  rich  mixture. 
They  are  also  common  when  running  at  slow  speeds.  Long  con- 
tinued, however,  they  constitute  a  nuisance  that  demands  earnes' 
and  careful  attention. 


ENGINE    OPERATION.  443 

Reducing  Smoke  in  the  Exhaust. — Smoke  from  the  exhaust 
being  a  sure  indication  of  oil  flooding  or  too  much  gasoline  in 
the  fuel  mixture,  demands  attention  to  the  oil  feed  and  carbu- 
retter, as  follows : 

1.  Reduce  rate  of  oil  feed,  if  the  smoke  indicate  oil.     If  this 
be  the  sole  trouble,  the  smoke  will  decrease  after  a  few  revolutions 
of  the  fly  wheel. 

2.  Restore  the  oil  feed  nearly  to  normal  and  adjust  the  car- 
buretter. 

3.  Examine  the  air  inlet  of  the  carburetter,  and  cleanse  the 
gauze  screen  of  any  dust.    This  will  restore  the  air  supply. 

Dangers  of  a  Smoky  Exhaust. — A  smoky  exhaust,  indicating 
the  presence  of  excess  oil  or  carbon  deposits  in  the  cylinder, 
should  serve  as  a  warning  in  one  respect.  The  soot  formed  is 
liable  to  take  fire  and  smolder,  causing  pre-ignition,  even  back- 
firing, particularly  under  heavy  loads. 

If,  after  other  relief  measures  have  been  tried,  the  nuisance  persist,  the 
cylinder  interior  should  be  cleaned  at  the  earliest  opportunity.  This, 
of  course,  cannot  be  done  until  the  engine  is  brought  home  and  can  be 
dismantled  at  leisure.  To  forestall  further  mishaps,  the  journey  should 
be  continued  with  as  weak  a  mixture  as  possible. 

In  cold  weather  considerable  watery  vapor  appears  in  the  exhaust. 

Causes  of  Defective  Mixtures. — An  over  rich  mixture — one 
containing  an  excess  of  gasoline  vapor — may  be  caused  by : 

1.  An  air  inlet  clogged  with  dust  or  ice  on  the  gauze. 

2.  A  piece  of  grit  or  other  object  preventing  closure  of  the 
needle  valve. 

3.  A  leaky  float,  which  has  become  partially  filled  with  liquid 
gasoline,  and  is,  therefore,  imperfectly  buoyant. 

A  leaky  float  may  be  repaired  by  soldering,  but  authorities  recommend 
that,  in  this  work,  a  vent  be  made  at  some  convenient  point,  and  the  float 
cooled  by  setting  on  a  cake  of  ice,  after  which  the  vent  is  soldered  up, 
leaving  the  air  within  at  atmospheric  pressure. 

A  poor  mixture  may  be  caused  by : 

1.  An  excess  of  air  drawn  through  some  leak  in  the  air  pipe. 

2.  Water  in  the  gasoline. 

3.  A  feed  pipe  or  feed  nozzle  clogged  with  lint,  grit  or  other 
obstructions. 


444  SELF-PROPELLED   VEHICLES. 

It  may  occasionally  happen,  particularly  after  standing  for  a  long  period, 
that  the  valve  of  the  carburetter  sticks.  This  will  interfere,  of  course, 
•with  proper  feed  of  fuel.  To  determine  whether  all  parts  are  in  good  con- 
dition, it  is  desirable  to  flush  or  prime  the  carburetter  by  depressing  the 
protruding  end  of  the  valve  spindle  or  the  flusher.  This  depresses  the  float, 
opens  the  valve,  allowing  liquid  to  enter  the  chamber,  and  thus  proves  that 
there  is  no  clog  or  interference. 

Under  conditions  of  operation,  the  carburetter  should  not  be 
allowed  to  flood.  However,  at  starting  it  is  often  a  means  of 
insuring  sufficient  richness  of  mixture  to  enable  ignition  to  take 
place.  A  sufficiently  rich  mixture  for  starting  may  be  obtained 
by  partially  closing  by  hand  the  air  inlet  to  the  carburetter  so 
that  the  increased  suction  will  draw  a  greater  quantity  of  gaso- 
line into  the  mixing  chamber. 

The  quality  of  the  mixture  may  generally  be  determined  from 
the  effects  on  the  operation  of  the  engine.  If  it  be  not  obvious 
in  this  manner,  it  may  be  determined  by  actual  test. 

If  the  cylinder  cock  or  the  spark  plug  be  removed  and  a  lighted 
match  applied  the  richness  of  the  mixture  may  be  judged  by  the 
color  of  the  flame,  viz : 

1.  If  the  mixture  be  too  rich,  it  will  burn  yellows 

2.  If  the  mixture  be  too  poor,  it  may  not  burn  at  all  or  faintly 
blue. 

3.  If  the  mixture  be  just  right,  it  will  explode  and  rush  out  of 
the  opening  to  the  danger  of  one's  fingers. 

4.  If  the  mixture   seem  to  be  poor,   injecting  a  little  gaso- 
line Trom  a  squirt  can,  or  flooding  the  carburetter,  will  prove 
whether  or  not  the  diagnosis  be  correct. 

Misfiring:  Defective  Mixture. — A  defective  mixture  will 
frequently  occasion  misfiring,  on  account  of  difficulty  of  igniting. 
Such  a  defective  mixture  may  be  one  that  is  either  too  rich  or  too 
weak,  and  may  be  produced  by  a  flooded  carburetter,  or  one  in 
which  sticking,  or  some  similar  disorder,  prevents  the  feeding  of 
sufficient  gasoline  spray  for  a  good  mixture. 

In  either  case  the  ignition  of  the  charge  is  slow,  if  it  occur 
at  all,  and  the  result  is  that  unburned  gas  is  discharged  into  the 
muffler,  producing  after  firing  and  reducing  the  power  efficiency. 


ENGINE    OPERATION.  445 

After  Firing:  Defective  Mixture. — After  firing,  or  "barking," 
consists  of  a  series  of  violent  explosions  in  the  muffler,  is  com- 
monly caused  by  misfires  in  one  or  more  cylinders,  permitting  the 
accumulation  of  unburned  gas  in  the  muffler,  which  is  ignited  by 
heat  of  the  walls  or  by  the  exhaust  of  firing  cylinders.  Some- 
times it  may  be  due  to  a  mixture  that  is  too  rich  or  too  weak, 
and  hence  burns  slowly,  continuing  its  combustion  after  passing 
into  the  exhaust.  It  also  occurs,  not  infrequently,  when  the  spark 
is  retarded. 

No  particular  harm  results  from  this  rather  startling  effect,  since  the 
explosion  can  seldom  occur  until  the  unburned  gas  comes  into  contact  with 
the  outer  air. 

Water  in  the  Carburetter. — This  will  often  prevent  starting 
of  the  engine,  and  will  always  impair  its  efficiency.  Water  is  very 
frequently  present  in  gasoline,  and,  particularly  when  the  tank  is 
low,  is  liable  to  get  into  the  pipes  and  carburetter.  Every  car- 
buretter has  a  drain  cock  at  the  bottom  to  let  off  the  water  that 
settles  from  the  gasoline.  The  natural  result  of  water  in  the 
carburetter  is  impaired  or  interrupted  vaporization  of  gasoline. 

In  cold  weather,  also,  the  water  is  liable  to  freeze,  preventing  the  action 
of  the  carburetter  parts  and  clogging  the  valves.  Ice  in  the  carburetter 
can  be  melted  only  by  the  application  of  hot  water,  or  some  other  non- 
flaming  heat,  to  the  outside  of  the  float  chamber. 

It  is  not  at  all  necessary  to  drain  the  carburetter  before  every  starting, 
but  after  a  prolonged  period  of  inactivity  it  is  desirable  to  give  the  water 
an  opportunity  to  escape.  A  strong  presumption  of  water  in  the  carburetter 
is  established  when  the  engine  starts,  runs  fitfully,  or  irregularly,  and 
finally  stops. 

Stale  or  Low  Degree  Gasoline. — Another  condition  that  will 
produce  some  of  the  same  symptoms  is  low  grade  or  stale  gaso- 
line. These  two  varieties  of  spirit  are  practically  identical,  in 
effect  at  least,  both  being  characterized  by  a  lower  specific  gravity 
than  is  required  for  readily  forming  a  fuel  mixture. 

Gasoline,  or  petrol  spirit,  as  it  is  called  in  England,  should  have 
a  specific  gravity  of  about  .682,  or  76° B.  Some  English  authori- 
ties recommend  spirit  having  a  specific  gravity  of  from  .72  to  .74, 
or  between  65°  and  59° B,  virtually  what  is  known  in  the  United 
States  as  high  grade  benzine.  Hydrocarbon  spirits  of  lower  de- 
grees on  the  Baume  scale  become  increasingly  difficult  to  vaporize. 


446  SELF-PROPELLED   VEHICLES. 

Gasoline,  being  a  volatile  essence  distilled  from  petroleum  oil  at  ten> 
peratures  ranging  between  122°  and  257°  F.,  and  boiling  at  between  149° 
and  194°,  on  the  average,  is  a  compound  of  several  spirits  of  varying 
density,  gravity  and  volatility. 

It  follows,  therefore,  that,  unless  stored  in  an  air  tight  vessel,  the 
lighter  constituents  are  liable  to  escape,  leaving  a  residue  that  will  show 
a  registry  on  the  Baume  scale  below  that  found  easiest  to  vaporize.  This 
is  the  process  that  occurs  in  the  carburetter,  if  gasoline  be  allowed  to  stand 
in  it  for  any  length  of  time.  It  is  always  best,  therefore,  on  storing  a 
vehicle  for  a  protracted  period,  or,  in  the  event  of  failure  to  start  the 
engine,  after  such  extended  inactivity,  to  drain  the  carburetter. 

Of  course,  if  the  tank  be  found  to  contain  only  low  degree  liquid,  the 
only  alternative  is  to  empty  it  and  refill  with  a  supply  of  the  proper 
quality. 

Failures  with  Four  Cylinders. — Unless  the  ignition  circuit  be 
elsewhere  disarranged — in  battery,  coil  or  wiring — failure  to  start 
in  a  four  cylinder  engine  is  probably  due  to  cause?  other  than 
foul  or  defective  spark  plugs.  It  may  happen,  however,  that 
one,  or  even  two,  of  the  cylinders  will  fail  to  ignite.  This  con- 
dition will  show  symptoms  similar  to  those  caused  by  misfiring, 
irregular  movement  and  vibration. 

Testing  for  the  Missing  Cylinder. — In  practically  all  four 
cylinder  engines  made  at  the  present  day  the  cranks  of  the  second 
and  third  cylinders  are  in  line,  and  are  set  at  180°  to  the  cranks 
of  the  first  and  fourth,  which  are  also  in  one  line.  Consequently, 
the  pistons  of  the  second  and  third  cylinders  make  their  in  strokes 
at  the  same  time  as  the  first  and  fourth  make  their  out  strokes. 
As  a  rule,  the  order  of  ignition  is:  first,  third,  fourth,  second, 
which  is  also  the  order  in  which  the  primary  circuit  is  closed  by 
the  timer,  closing  the  circuits  through  the  primary  winding  of 
each  coil  in  succession. 

In  order,  therefore,  to  determine  which  cylinder,  if  any,  is 
missing  fire,  it  is  necessary  only  to  open  the  throttle  and  advance 
the  spark  lever  to  the  running  position,  giving  the  engine  good 
power,  and  to  cut  out  three  of  the  four  cylinders  by  depressing 
their  coil  vibrators.  If  the  engine  continue  to  run  with  coils  2, 
3  and  4  cut  out,  cylinder  i  is  evidently  working  properly.  De- 
pressing vibrators  of  I,  3  and  4  shows  whether  2  is  working;  of 
I,  2  and  4,  whether  3  is  working,  and  of  I,  2  and  3,  whether  4 
is  working.  On  discovering  the  faulty  cylinder,  its  plug  may  be 
tested  precisely  as  is  the  plug  of  a  single  cylinder  engine. 


ENGINE    OPERATION.  447 

A  precisely  similar  method  may  be  followed  in  the  search  for 
a  missing  cylinder  of  a  three  or  six  cylinder  engine. 

A  missing  cylinder  may  also  be  found  by  the  low  temperature 
of  its  spark  plug  exhaust  pipe,  if  the  missing  be  long  continued. 

Difficulty  in  Starting. — Sometimes  an  engine  will  start  badly, 
but  will  run  well  after  attaining  a  high  speed.  Among  the  vari- 
ous causes  which  contribute  toward  bringing  about  this  condition 
may  be  mentioned : 

i.  An  obstruction  in  the  jet  of  the  carburetter,  causing  trou- 
ble in  starting,  when  removed  by  the  suction  allows  the  engine  to 
speed  up  and  run  well  at  high  speed. 

2.  A  too  weak  suction  in  starting;  this  may  be  remedied  by 
partially  closing  the  air  inlet  while  cranking,  or  giving  the  throt- 
tle more  opening. 

3.  Insufficient  tension  of  the  auxiliary  air  valve  spring. 

4.  The  spark  not  sufficiently  retarded. 

Running  Down. — When  the  engine  starts  well,  runs  for  a 
while,  then  slows  down  and  stops,  there  are  many  condi- 
tions to  which  it  may  commonly  be  attributed.  Among  these  are : 

1.  Water  or  sediment  in  the  carburetter. 

2.  Loose  connections,  breakdowns,  or  any  other  disarrange- 
ment of  the  ignition,  such  as  would  otherwise  interfere  with  start- 
ing. 

3.  A  weak  or  imperfectly  recuperated  battery — frequently  the 
latter — that  suddenly  fails  to  supply  current. 

4.  A  leak  in  the  water  jacket  that  admits  water  to  the  com- 
bustion space. 

5.  Seizing  of  the  piston  in  the  cylinder  on  account  of  failure 
of  the  cooling  system.    This  may  result,  in  a  water  cooled  cylin- 
der, from: 

a.  Exhaustion  of  the  water; 

b.  Stoppage  in  the  pipes  or  pump; 

c.  Breakdown  of  the  pump; 

d.  Failure  of  the  oil  supply; 

In  an  air  cooled  cylinder  seizing  may  result  from : 

a.  Insufficient  radiation  surface ; 

b.  Obstructed  air  circulation. 


448  SELF-PROPELLED   VEHICLES. 

6.  Heated  bearings  that  seize  and  interfere  with  operation. 

7.  Poorly  matched  or  poorly  adjusted  new  parts,  particularly 
pistons,  that  cause  heating  and  perhaps  seizing  from  friction. 

8.  Lost  compression  from  broken  or  stuck  valves,  leaky  piston, 
etc.,  as  explained  in  the  succeeding  paragraph. 

Running  with  Switch  Off. — A  peculiar  condition  in  engine 
operation,  sometimes  encountered,  is  the  running  of  the  engine 
after  the  switch  has  been  opened.  It  occasionally  happens  that 
the  switch  becomes  defective,  so  that  it  does  not  break  the  circuit 
when  in  its  "off"  position.  A  most  common  cause  for  running 
with  open  switch  is  red  hot  plug  points,  also  the  heating  to  incan- 
descence of  some  small  particle  in  the  cylinder,  either  loose  or 
attached  to  the  interior  surfaces. 

Pre=ignition. — An  incandescent  particle  or  overheated  cylin- 
der will  cause  an  engine  to  pre-ignite. 

Sometimes  the  rotor  arm  of  the  timer  wears  at  the  contact  point 
leaving  a  path  of  metallic  particles  on  the  ring  containing  the 
stationary  contacts,  thus  causing  the  current  to  flow  to  the  station- 
ary contact  via  this  path  and  cause  ignition  to  occur  before  the 
proper  time. 

Loss  of  Power  without  Misfiring. — The  chief  cause  for  an 
engine  to  fail  to  deliver  its  full  power  is  poor  compression.  A 
fuel  mixture  either  too  weak  or  too  strong  will  reduce  the  power 
of  the  engine. 

If  the  bearings  be  too  tight  there  will  be  a  loss  of  power  due  to  the 
additional  friction  set  up ;  bearings  when  too  tight  will  heat  and  a  touch 
of  the  hand  will  give  indication  of  their  condition. 

Another  source  of  loss  of  power  is  a  defective  clutch  which  slips  and 
does  not  transmit  all  the  power  delivered  by  the  engine. 

Brake  rods  sometimes  get  out  of  adjustment,  allowing  the  band  to 
remain  in  contact  with  the  drum,  thus  absorbing  more  or  less  power. 

Low  Compression  Troubles. — When  little  or  no  compression 
manifests  itself  as  a  resistance  to  the  turning  of  the  crank,  it  is 
certain  that  the  operation  of  the  engine  will  be  defective,  provided 
it  can  be  started  at  all.  If  the  engine  lose  compression  after  it 
has  started,  it  will  misfire  and  slow  down. 


ENGINE    OPERATION.  449 

Low  compression  means  absence  of  a  sufficient  quantity  of  gas 
mixture  to  give  a  good  power  effect.  This  absence  results  from 
a  leak  in  the  combustion  chamber,  due  to : 

1.  A  sticking  inlet  valve — if  the  inlet  be  automatic — from  an 
incrustation  of  oil  gum.    Sticking  may  be  also  d^e  to  other  causes. 

2.  Pitted  or  corroded  exhaust  valve. 

3.  A  weak  spring  on  the  exhaust  valve. 

4.  Loose  or  open  compression  tap. 

5.  A  leaky  piston,  due  to : 

a.  Worn  or  broken  piston  rings. 

b.  Piston  rings  worked  around,  so  as  to  bring  the  openings  on  their 
circumferences  into  line. 

6.  A  blown  out  gasket  in  the  cylinder  head. 

7.  Worn  or  loose  thread  at  the  insertion  of  the  spark  plug. 

8.  A  broken  valve  or  valve  stem. 

9.  Worn  or  scratched  sweep  wall,  due  to  lack  of  oil  or  the 
presence  of  grit. 

10.  A  valve  stem  that  is  so  long  as  to  touch  the  end  of  the 
pushrod  when  the  engine  is  cold.     The  remedy  for  this  is  to  file 
the  end  of  the  valve  stem  until  a  card  may  be  inserted  between 
its  end  and  the  end  of  the  pushrod. 

When  the  compression  is  low  all  the  joints  and  cylinder  gaskets 
should  be  examined  for  leaks. 

The  escape  of  compression  around  the  spark  plug,  relief  cock 
or  other  opening  into  the  cylinder  may  be  detected  by  the  applica- 
tion of  a  little  soapy  water ;  if  there  be  a  leak  it  will  be  indicated 
by  the  formation  of  bubbles. 

A  leaky  piston  is  indicated  by  a  hiss  inside  the  cylinder  due 
to  worm  rings  or  the  openings  in  the  ring  having  worked  around 
in  line  with  each  other.  A  sharp  hiss  indicates  a  broken  ring. 

Carbonized  Cylinders. — An  annoyance  with  which  almost 
every  motorist  has  to  contend  more  or  less  is  the  deposit  of  a  hard, 
indurated  form  of  carbon,  similar  to  gas  carbon,  upon  the  walls 
of  the  cylinders  and  valve  chambers.  This  carbon  is  a  product 
of  heat  decomposition  of  the  fuel  or  the  lubricant,  or  both,  un- 
der pressure,  and  in  the  presence  of  too  little  air  for  combustion. 


450  SELF-PROPELLED  VEHICLES. 

The  formation  of  carbon  within  the  cylinder  is  generally  in- 
dicated by  the  frequent  occurrence  of  pre-ignition,  due  to  pro- 
jecting points  of  red  hot  carbon  within  the  cylinder.  Its  forma- 
tion can  be  avoided  almost  altogether  by  close  attention  to  the 
lubrication,  valve  and  ignition  timing,  and  carburetter  adjust- 
ments. 

Too  rich  a  mixture  almost  invariably  results  in  carbonization,  which  also 
follows  upon  the  use  of  oils  that  do  not  stand  high  enough  temperatures, 
or  that  are  otherwise  of  poor  quality. 

Likewise,  delayed  opening  of  either  exhaust  or  inlet  valves,  in  the  one 
case  not  providing  free  exit  for  the  exhaust  and  in  the  other  cutting  down 
the  time  for  combustion,  will  tend  to  produce  carbonization. 

It  is  not  possible  to  avoid  carbonization  altogether  and  even 
in  the  best  cars,  perfectly  adjusted,  the  deposit  will  slowly  accumu- 
late. To  keep  it  to  a  minimum,  the  often  recommended  process 
of  coal  oiling  the  cylinders  from  time  to  time  is  to  be  advised,  but 
even  with  this  preventative  regularly  applied  it  occasionally  be- 
comes necessary  to  take  off  the  cylinders,  scrape  out  the  com- 
bustion chambers  and  clean  off  the  valves  and  pistons. 

Carbon  when  present  in  lumps  will  tend  to  become  red  hot  and  thus 
occasion  pre-ignition.  Small  particles,  too,  may  catch  on  the  valve  seats, 
holding  the  valves  open  and  causing  loss  of  compression  and  power;  or  if 
the  valve  heads  are  of  the  cast  iron  type,  their  breakage  by  the  forced 
uneven  seating.  The  carbon  that  catches  in  the  piston  rings  and  their 
grooves  may  so  bend  the  rings  as  to  prevent  their  even  contact  with  the 
cylinder  walls,  so  essential  to  good  compression,  and  in  addition  may 
badly  score  the  cylinders. 

In  scraping  off  these  carbon  deposits  it  is  necessary  to  use  hard,  sharp- 
edged  or  pointed  tools  for  scrapers,  and  to  apply  them  vigorously  and 
thoroughly  to  every  part  that  presents  the  objectionable  coating. 

For  cleaning  out  the  ring  grooves  it  usually  will  be  found  desirable  to 
expedite  the  work  by  grinding  a  special  tool,  made  to  fit  so  closely  as  to 
leave  no  deposit  under  its  end  or  by  its  edges. 

Keeping  the  deposits  moist  with  kerosene  will  facilitate  their  removal; 
soaking  them  with  kerosene  for  hours  or  even  days  will  be  still  better. 
For  surfaces  that  can  be  reached  in  this  manner,  and  that  will  not  be  in- 
jured by  the  wear  it  will  cause,  finishing  may  be  done  with  coarse  emery 
cloth,  held  in  the  hand  or  around  a  stick,  if  circumstances  may  require. 

It  is  to  be  understood  that  it  is  a  rather  long  and  tiresome  job  at  best, 
to  thoroughly  clean  all  parts  of  a  badly  carbonized  engine,  but  the  im- 
provement in  its  power  and  running  afterwards  will  more  than  compen- 
sate for  the  work  expended  by  the  owner. 

A  simple  and  effective  method  of  removing  carbon  consists  of 
inserting  into  the  cylinder  a  set  of  scouring  rings  and  operating 
the  engine  for  a  few  minutes  on  the  remaining  cylinders. 


AN   AMERICAN 


A— Gasoline  Tank. 
B— Oil  Tank. 


C— Carburetter. 
D — Cam  Case. 


E-Prin 
Bn 


SOL/HIE    MOTOR    BICYCLE. 


F-Battery. 

G— Induction  Coll. 


H— Muffler. 

J— Grip  Control  Lever. 


CHAPTER  THIRTY-FOUR. 

MOTOR  CYCLES. 


Requirements  of  a  Motor  Cycle. — According  to  experience 
in  the  matter,  a  motor  cycle  must  be  propelled  by  an  air  cooled 
engine,  preferably  of  rather  high  speed  and  of  somewhat  higher 
power  rating  than  is  actually  required  for  the  load  to  be  carried. 
The  reasons  for  both  conditions  are  readily  discoverable,  since, 
having  dispensed  with  the  water  cooling  and  circulating  system 


FIG.  314.-A  belt  drive  motor  cycle.    As  shown  the  tension  of  ^e  belt  is  adjusted  by 
changing  the  position  of  the  rear  wheel  axle.    Another  method  of  regulating  tr 
belt  tension  is  by  means  of  an  adjustable  idler  pulley,  illustrated  in  fags,  or,  ana 
328.    The  above  cut  shows  the  general  arrangement  of  the  various  parts,  sucn  as, 
carburetter,  gasoline  tank,  ignition  system,  etc. 

for  sake  of  lightness  and  compactness,  it  is  desirable  to  avoid 
such  causes  of  overheating  as  unusually  high  speeds,  and  such 
low  power  as  would  cause  the  engine  to  labor  under  ordinary 
loads.  Some  bicycles  have  been  constructed  for  racing  purposes, 
with  an  advertised  speed  of  60  miles  per  hour  and  over,  several 
of  them  having  been  equipped  with  an  engine  guaranteed  to  de- 

451 


453  SELF-PROPELLED    VEHICLES. 

velop  seven  horse  power,  a  rating  far  in  excess  of  demands  for 
carrying  one  person  over  an  even  roadway.  At  best,  such  ma- 
chines are  bulky  and  heavy,  out  of  all  proportion  to  convenience 
of  handling  or  for  ordinary  service.  Even  with  some  machines 
designed  for  ordinary  road  service,  and  having  an  extreme  speed 
limit  of  more  than  25  or  30  miles  per  hour,  the  motor  used  is 
guaranteed  to  develop  2,  and  even  3  horse-power  at  between 
1,200  and  1,500  revolutions  per  minute — speeds  seldom  attempted. 

The  Framework  and  Wheels. — The  framework  and  wheels 
of  motor  bicycles  are,  of  course,  stronger  and  heavier  than  in 
foot  propelled  machines.  The  tubes  are  made  with  thicker  walls, 
and  the  joints  are  more  securely  reinforced.  In  several  makes 
the  end  of  security  is  further  assured  by  struts  and  trusses,  par- 
ticularly at  the  fork  on  the  steering  post  and  at  the  place  where 
the  motor  is  hung.  The  diamond  frame  is  practically  universal, 


PIG.  315. — A  motor  cycle  frame.  The  lower  member  is  curved  to  conform 

to    the   shape    of   the   crank  case   of   the    engine.      The    fork    consists 

of   two    hinged    pieces    held  in   place    by   a   spring-   forming   a    shock 
absorbing  device. 

although  several  of  the  earlier  types — notably  the  Wolfmuller 
and  Lawson — used  the  drop  frame.  In  the  Holden  bicycle  the 
frame  consisted  of  a  single  tube,  joined  to  the  steering  post  in 
front  and  bent  downward  to  carry  the  drive  wheel  in  a  fork  at 
the  rear.  The  back  stays  were  extended  forward  to  hold  the 
motor  and  other  apparatus,  and  were  further  supported  from  the 
main  tube  by  a  dropping  tubular  member  at  front  and  rear. 
The  pedals  in  this  machine  were  geared  to  the  forward  wheel,  as 
in  old  fashioned  velocipedes. 


MOTOR    CYCLES. 


453 


The  Engine. — The  one  cylinder  four  cycle  engine  is  the  type 
in  general  use  on  motor  cycles,  although  two  and  four  cylinder 
engines  are  used  on  the  higher  powered  machines. 

The  "V"  twin  cylinder  engine,  as  shown  in  fig.  316  is  a  popular 
type  on  account  of  its  simplicity  and  lightness,  there  being  only 
one  crank  and  cam  shaft  for  the  two  cylinders. 

The  engine  is  placed  in  very  low  position  so  as  to  keep  the  center  of 
gravity  or  weight  low  and  make  the  machine  easy  to  balance.  With  this 
location,  the  rider  does  not  have  to  straddle  a  hot  engine  and  the  air 
strikes  directly  on  the  cylinder  head  of  the  engine. 


FIG-  316. — Sectional  view  of  a  "V"  twin  cylinder  motor  cycle  eng-Ine.  This 
type  is  in  general  use  on  the  higher  powered  machines.  Simplicity 
and  lightness  are  secured  in  this  design  as  one  cam  shaft  and  a 
single  crank  suffice  for  the  two  cylinders. 


454 


SELF-PROPELLED    VEHICLES. 


Arrangement  of  the  Engine. — In  the  arrangement  of  the 
engine  on  a  bicycle  there  has  been  a  wide  diversity  of  design.  In 
some  makes  it  has  been  supported  on  the  back  stays,  between  the 
pedal  bearing  and  the  rear  wheel ;  in  one  make,  on  an  extension 
of  the  back  stays  to  rear  of  the  wheel;  in  several  makes  it  is 
supported  against,  or  forms  a  part  of  the  rear  or  saddle  tube 


FIG.  317. — The  F.  N.  four  cylinder  motor  cycle  engine.  The  spark  plugs 
are  secured  to  the  top  of  the  cylinders,  provided  laterally  with  valve 
chambers  cast  with  them  in  one  piece.  At  the  back  end  of  the  crank 
case  is  an  oil  drip  cup  which  collects  the  oil  discharged  by  the 
journals  of  the  chank  shaft,  and  sends  it  back  through  a  conduit 
into  the  botom  of  the  crank  case.  The  exhaust  valves  are  fitted 
with  a  lifting  mechanism.  Small  levers  operating  same  are  con- 
nected by  a  system  of  rods  to  a  lever  on  the  handle  bar,  which  the 
rider  moves  to  lift  the  valves. 

member  of  the  "dimond"  frame.  The  favorite  position  with 
most  machines  at  the  present  time  is  on  the  forward  member  of 
the  frame,  in  front  of  the  pedal  bearing,  or  on  a  tube  arranged 
beneath,  and  suitably  trussed  to  hold  the  weight. 

Cooling  System  and  Lubrication. — Motor  cycle  engines  are 
always  air  cooled.  As  the  engine  has  at  times  to  run  at  very  high 
speed,  the  average  temperature  of  the  cylinder  walls  is  higher 
than  with  engines  running  at  more  moderate  speeds,  hence  it  is 
important  that  the  cylinder  be  properly  lubricated.  A  high  fire 
test  grade  of  oil  must  be  used. 


MOTOR    CYCLES. 


455 


The  splash  system  of  lubrication  is  employed ;  oil  is  placed  in 
the  crank  case  and  the  motion  of  the  flywheel  and  connecting  rod 
end  splashes  it  on  all  bearings  and  on  the  piston  and  cylinder 
walls. 


FIG.  318. — Cylinder  head  and  valves  of  the  Indian  motor  cycle.  Both  in- 
let and  exhaust  valves  are  placed  in  the  same  pocket.  The  inlet 
valve  of  the  twin  is  operated  by  a  lift  rod,  operated  by  the  cam,  and 
a  rocking  lever  that  is  mounted  on  the  dome  of  the  valve  chamber, 
and  an  adjusting  screw  is  provided  in  the  end  of  this  rocking  lever 
to  regulate  the  amount  of  the  opening  of  the  valve.  The  valve 
chamber  dome  is  secured  in  position  by  a  bayonet  joint,  and  may  be 
removed,  after  disconnecting  the  induction  pipe,  by  giving  it  a 
quarter  turn.  The  inlet  valve,  with  its  seat,  spring,  etc.,  come  out 
with  the  dome,  from  which  they  are  withdrawn  by  the  fingers.  The 
removal  of  the  dome  exposes  the  exhaust  valve  for  inspection. 


The  Valve  Gear. — The  valves  are  offset  on  one  side  of  the 
cylinder,  being  arranged  one  above  the  other.  The  inlet  valve  is 
usually  of  the  automatic  type  while  the  exhaust  is  always  opened 
mechanically  by  a  cam. 


456 


SELF-PROPELLED    VEHICLES. 


FIG.  319. — Interior  view  of  a  twin  cylinder  crank  case  with  flywheels,  con- 
necting rods,  and  the  t\yo  to  one  gears  which  operate  the  valve 
mechanism  and  the  ignition  apparatus,  whether  that  be  of  the  bat- 
tery type  or  magneto.  In  this  illustration  an  oil  reservoir  is  shown 
and  in  the  right  hand  half  of  the  base  is  seen  the  little  window 
through  which  the  oil  level  can  be  observed. 


FIG.  320. — Valve  gear  of  the  Indian  motor  cycle.  As  shown  in  the  Illustra- 
tion, the  inlet  valve  of  the  front  cylinder  is  about  to  close,  while 
the  exhaust  valve  of  the  rear  cylinder  has  just  opened.  It  will  he 
seen  that  the  revolving  cam  acts  on  the  end  of  a  cam  lever,  while 
the  cam  upon  the  lever  lifts  a  second  lever,  or  finger,  upon  which 
the  lower  end  of  the  inlet  valve  operating  rod  rests.  The  exhaust 
valve  is  operated  in  the  same  way,  but  the  levers  are  of  slightly 
different  form,  and  the  end  of  the  cam  lever  is  provided  with  a  steel 
roller  to  lessen  the  friction  with  the  revolving  cam,  as  the  power 
required  to  operate  the  exhaust  valve  is  greater  than  that  required 
for  the  inlet  valve. 


MOTOR   CYCLES. 


457 


It  is  usual  to  fit  the  exhaust  valve  with  a  lifter  to  hold  the  valve 
off  its  seat  and  thus  relieve  compression  in  starting.  This  is 
operated  by  a  lever  conveniently  located.  A  spiral  spring  effects 
the  return  of  the  lever  to  its  normal  position. 

Ignition  and  Control.— Motor  cycles  manufactured  in  America 
use  jump  spark  ignition,  almost  without  exception.  Few  of  them 
also  have  any  regulating  devices  other  than  levers  for  varying 
the  time  of  the  spark  and  the  opening  of  the  valves — thus  modi- 


FIG.  321. — Diagram  of  battery  and  coil  connections  for  Jump  spark  Igni- 
tion as  applied  to  a  motor  cycle.  C9ils  are  usually  plainly  labeled 
with  the  abbreviations:  "Bat.,"  "Pri.,"  "Sec.,"  indicating-  that  the 
Wires  are  to  be  connected  to  the  battery,  the  primary  circuit  or  con- 
tact maker,  and  the  spark  plug.  The  battery  and  primary  wires 
being  for  the  low  tension  circuit  are  easily  distinguished  from  the 
secondary  wire  by  the  small  amount  of  insulation  surrounding  them. 

fying  the  speed — and  a  cut  out  switch  located  conveniently  on  the 
handle  bars,  for  the  purpose  of  stopping  the  engine.  Adjusting 
the  mixture  and  varying  the  time  of  the  spark  are  the  typical 
means  provided  for  changing  the  speed. 

Ignition  current  is  usually  obtained  from  a  battery  of  three 
dry  cells ;  on  the  multi-cylinder  machines  a  magneto  is  frequently 
used.  When  a  battery  is  used,  a  contact  maker  is  provided  for 
controlling  the  primary  current 


458 


SELF-PROPELLED    VEHICLES. 


It  is  attached  to  the  cam  shaft  of  the  engine  and  the  time  of  spark  Is 
regulated  by  rotating  it  around  the  cam  shaft.  Timing  devices  of  this  class 
are  fully  described  in  the  chapter  on  ignition  and  the  method  of  wiring 
is  illustrated  in  fig.  321. 

The  low  tension  wires  may  be  distinguished  by  the  small  amount  of 
insulation  surrounding  them  as  compared  with  the  secondary  or  plug  wire. 

The  primary  circuit  is  completed  by  a  ground  connection 
through  the  engine  and  frame.  The  three  terminal  cartridge  typo 
of  coil  is  generally  used  as  shown  in  fig.  321.  Where  the  ter- 
minals are  not  marked,  it  is  easy  to  distinguish  the  high  tension 
or  secondary  wire  by  its  size,  while  almost  without  exception,  the 
wires  at  the  other  end  of  the  coil  are  to  be  connected  to  the 
battery  and  contact  maker. 


FIG.  322. — Handle  bar  of  the  Indian  motor  cycle  with  grip  control.  A  twist 
of  the  right  wrist,  operates  the  spark  and  exhaust  valve.  This  con- 
trols the  speed  of  the  machine  to  a  certain  extent.  When  more  speed 
or  more  power  is  required,  a  twist  of  the  left  wrist  operates  the 
throttle  and  applies  the  reserve  power  which  is  necessary  when  steep 
hills  or  sand  roads  are  encountered. 

In  a  few  cases,  a  four  terminal  coil  is  employed  which,  though  apt  to  be 
confusing  at  first,  need  not  complicate  the  matter  of  connecting  it  up  in 
the  machine  if  only  it  be  remembered  that  the  fourth  terminal  is  nothing 
more  nor  less  than  a  ground  wire  for  the  secondary  coil,  and  should, 
therefore  be  connected  to  some  metal  portion  of  the  machine  in  a  secure 
manner. 

Usually  some  indication  on  the  outside  of  the  case,  prevents  any  danger 
of  confusion. 

The  method  of  connecting  the  wiring  for  multi-cylinder  engines  is  ex- 
actly the  same  as  it  would  be  were  each  cylinder  a  separate  engine  in  all 
respects,  save  that  but  one  battery  is  used. 


MOTOR   CYCLES. 


459 


FIG  323.— Spring  fork  and  handle  bar  of  the  Thiem  motor  cycle.  The 
narts  the  fork  are:  A,  main  fork;  B,  auxiliary  fork;  CC,  ball 
belong  shackles?  D  inner  shell  screwed  into  fork  crown;  B.  outer 
ell  screwed  into  swivel  collar  F;  F,  swivel  collar;  G,  spring;  H, 
plunger  bearing  on  spring  G  and  forming  air  tight  compartment;  I 
stem  fastened  into  plunger  hand  cap  J;  J.  cap  screwed  into  outer 
shell  E;  K.  collar  forming  air-tight  compartment.  It  will  be  noticed 
that  air  tight  compartments  are  formed  between  cap  J  and  collar  K 
also  collar  K  and^  Plunger  H.  As  an  extra  Precaution  a  rubber 
washer  is  placed  between  J  and  K  and  K  and  H. 
of  the  handle  bar  are:  L.  handle  bar;  M  sleeve  revolv- 
ing; N,  sleeve  end  drop  forging;  O,  ball  and  socket  joints  adjust- 
able- P  rod  right  thread  at  one  end  and  left  thread  at  other  end,  Q, 
be  1  crank?  R  bel  crank.  It  will  be  seen  that  by  revolving  sleeve 
M  that  rod  P  will  move  in  and  out  in  a  horizontal  Direction.  This 
will  cause  rod  Pa  to  move  through  bell  crank  R  and  cause  rod  PC 
to  move  forward  or  backward  and  thus  moving  spark  advance  or 
carburetter  throttle. 


460 


SELF-PROPELLED    VEHICLES. 


In  wiring  a  multi-cylinder  coil  then,  it  is  necessary  first  to  connect  the 
proper  terminal  to  the  battery  and  to  lead  each  of  the  primary  wires  to  the 
terminals  of  the  contact  maker. 

Jar  Absorbing  Devices. — One  great  disadvantage  in  motor 
cycle  construction  is  the  practical  difficulty  of  arranging  any 
form  of  spring  or  cushion  device  to  take  the  vibration  of  the 
engine. 

Several  makes  of  machines  include  some  spring  arrangement  in  the 
saddlepost  for  easing  the  rider,  but  the  framework  must  be  built  to  en- 
dure the  vibration  of  travel  on  rough  roads,  and  at  all  speeds.  The  wear 
and  strain,  as  may  thus  be  seen,  is  considerable. 

To  neutralize  this  element  the  engine  is  provided  with  heavy 
flywheels,  in  order  to  equalize  the  movement  as  far  as  possible. 

One  excellent  type  of  high  powered,  high  speed  machine,  which 
has  won  exceptional  records  in  a  number  of  tests  and  races,  has 


FIG.  324. — Sectional  view  of  the  N.  S.  U.  motor  cycle  switch  handle  The 
ignition  current  is  switched  on  by  turning  the  handle  to  the  left  and 
off  by  turning  the  handle  to  the  right.  The  parts  are  as  follows: 
7.  Switch  handle;  82.  A  metal  rod;  83.  Terminal  nuts;  84.  Non-con- 
ducting guide  block;  85.  Set  screw,  locking  to  the  handle  bar;  86 
Metal  compact  ring;  87.  Left  handed  nut  switch;  88.  Screws  or  in 
later  patterns,  cast  into  the  same.  In  assembling  these  parts  the 
insulated  wire  L  is  carefully  drawn  through  the  left  side  of  the 
handle  bar  tube  and  out  by  the  T  joint  of  the  same. 

an  extra  large  flywheel  (between  18  and  21  inches,  according  to 
power),  and  the  claims  are  that  this  "keeps  the  engine  steady  and 
does  away  with  the  heavy  vibration  in  some  high  powered 
machines."  For  machines  intended  for  ordinary  speeds  such 
additional  weight  is  hardly  necessary. 


MOTOR    CYCLES. 


461 


Valve  and  Spark  Timing. — With  some  types  of  engine,  the 
timing  of  the  valves  and  spark  is  fixed  so  that  unless  wrongly 
assembled  at  the  factory  there  is  no  chance  of  trouble  on  this 
score,  excepting,  of  course,  in  the  event  of  the  rare,  but  possible 
breakage  of  a  tooth. 


FIG.  325. — Timing  motor  cycle  valves.    After  removing  contact  maker  and 
gear  case  covers  and  the  large   gear,   1,   the  crank   is  placed   on   t 
upper    dead    centre,    and    2,    the    large    gear    and    cam    replaced,    t 
large   gear  meshing  with   its   driver   in  such   a  way   that   the  cam   it 
just  breaking  away  from  the  lifter  as  shown  in  the  figure.     The  gear 
case  cover  and  contact  maker  are  now  replaced.     The  proper  timing 
of  the  valve  causes  it  to  close  on  the  dead  centre. 

FIG.  326. — Usual  arrangement  for  spark  control  on  a  motor  cycle.  To 
time  the  spark,  1,  the  spark  lever  is  placed  in  such  a  position  that 
the  spark  will  be  half  way  advanced,  2,  the  crank  is  turned  through 
one  revolution  from  the  point  of  exhaust  closure,  3,  the  sparking 
cam  is  set  so  that  the  contact  spring  is  just  leaving  the  contact 
screw,  and  tightened  in  this  position. 

The  gear  teeth  which  mesh  in  order  to  give  the  correct  move- 
ments are  clearly  marked  either  with  lines  on  the  ends  of  the  gears 


462 


SELF-PROPELLED    VEHICLES. 


or  prick  punch  points,  which  in  any  case  should  be  made  to  reg- 
ister when  setting  up  the  motor.  Under  these  conditions  the  tim- 
ing  of  the  engine  should  be  a  comparatively  easy  task. 

If  for  any  reason  it  be  desired  to  retime  or  to  verify  the  timing 
independently,  methods  are  illustrated  in  figs.  325  and  326,  for 
performing  these  operations  and  described  in  the  text  accompany- 
ing same. 


FIGS.  327  and  328. — Illustrations  showing  the  operation  of  a  belt  drive.  The 
tension  of  the  belt  is  regulated  by  the  adjustable  idler,  the  two 
cuts  showing  the  "on"  and  "off"  positions  of  the  latter.  The  loca- 
tion of  the  idler  in  close  proximity  to  the  pulley,  causes  it  to  be 
more  fully  embraced  by  the  belt,  thus,  increasing  the  traction  area 
without  unduly  increasing  the  belt  tension. 

The  Drive. — There  are  three  methods  in  general  use  for  trans- 
mitting the  power  of  the  engine  to  the  rear  wheel,  viz : 

1.  Belt  drive; 

2.  Chain  drive; 

3.  Shaft  drive. 

The  belt  drive  was  the  first  method  of  power  transmission 
applied  to  the  motor  cycle  and  is  still  used  to  a  considerable 
extent.  It  has  the  objection  of  requiring  frequent  adjustment 


MOTOR    CYCLES. 


463 


and  must  be  kept  in  tight  contact  to  prevent  slippage  of  the  small 
driving  pulley  on  the  engine  with  the  consequent  loss  of  power. 

The  use  of  round,  V-shaped  and  even  flat  belts,  does  not  always  give 
satisfaction.  The  great  tension  to  which  the  belts  have  to  be  subjected 
in  order  to  ensure  proper  adhesion,  and  still  more  the  alternate  action  of 
dry  and  wet  weather,  cause  them  to  stretch.  This  drawback  frequently 
necessitates  repairs  on  the  road.  Finally,  the  traction  exercised  by  the 
belt  on  one  of  the  ends  of  the  hub,  hinders  the  proper  working  of  the  latter. 

Manufacturers  have  reduced  considerably  the  defects  of  belt 
drive  by  providing  belts  of  larger  and  better  form. 


FIG.  329. — The  F.  N.  shaft  drive.  It  consists  of  a  countershaft,  the  front 
rear  wheel.  It  is  operated  as  follows:  By  bringing1  the  hand  lever 
at  the  top  of  the  frame  tube  into  central  position  or  upright,  gives 
the  neutral  position  allowing  engine  to  run  free;  by  pulling1  the 
lever  backward  the  low  gear  is  obtained;  by  pushing1  the  lever  for- 
ward the  low  gear  is  disengaged  and  the  high  gear  is  brought  into 
action.  Two  brakes  are  incorporated  in  the  transmission. 

The  chain  and  shaft  drive  furnish  a  positive  connection  between 
the  engine  and  rear  wheel.  The  chain  drive  is  furnished  on  a 
number  of  the  medium  priced  machines  and  the  shaft  drive  on  the 
more  expensive  machines. 

While  the  chain  is  a  satisfactory  and  inexpensive  drive,  the 
shaft  with  its  enclosed  gears  is  entirely  protected  from  dust  and 
does  not  present  any  lubricated  surfaces  to  soil  the  rider's  clothing. 

Transmissions. — The  use  of  transmissions  on  motor  cycles  is, 
as  yet,  rather  limited;  the  control  of  the  machine  is  usually  by 
spark  and  mixture  adjustments  and  the  ignition  cut  out  switch 
on  the  handle  bar. 


464  SELF-PROPELLED    VEHICLES. 

It  would  of  course,  be  impracticable  to  equip  a  motor  cycle  with 
a  transmission  giving  the  number  of  changes  provided  for  auto- 
mobiles, however,  machines  are  now  to  be  had,  fitted  with  trans- 
missions giving  two  speeds  and  free  engine.  A  compact  trans- 
mission fulfilling  these  requirements  is  shown  in  fig.  330,  in 
addition,  two  brakes  are  incorporated  in  this  transmission  as 
shown  in  the  illustration. 

The  use  of  a  transmission  on  a  motor  cycle,  enables  the  rider, 
I,  to  climb  steeper  hills,  2,  makes  it  possible  to  stop  and  restart 
at  will  without  dismounting,  either  on  level  road  or  on  the  steep- 
est hill,  by  means  of  the  free  engine,  and  3,  to  slow  down  or  even 
come  to  a  dead  stop,  if  "pocketed"  in  congested  street,  and  restart 
without  pedaling. 

Instructions   for  Starting  and   Riding   Motor   Cycles. — In 

spite  of  the  numerous  improvements  which  have  been  made  in 
motor  cycles  in  the  last  few  years,  they  require  a  great  deal  of  at- 
tention, otherwise  the  machine  is  liable  to  become  disabled  on  the 
road.  It  is,  therefore,  important  to  pay  attention  to  all  the  parts 
of  the  machine.  Only  then  is  it  possible  to  obtain  full  satisfaction 
in  operating. 

Before  Starting. — As  a  preliminary  to  starting,  I,  the  various 
parts  of  the  machine  should  be  carefully  examined,  2,  the  gasoline 
tank  and  lubricating  devices  filled,  3,  gasoline  valve  opened,  4, 
carburetter  primed  and  throttle  opened,  5,  the  exhaust  valves 
raised,  6,  ignition  cut  out  plug  inserted,  7,  handle  bar  ignition 
switch  opened,  and  8,  spark  well  advanced  by  means  of  the  lever 
provided  for  the  purpose. 

Starting. — In  mounting  the  machine,  the  pedal  on  left  side 
of  machine  should  be  in  the  upper  position.  With  right  foot  on 
the  ground,  the  machine  standing,  the  rider  straddles  the  saddle 
and  starts  the  machine  by  pressure  of  the  left  foot  on  the  raised 
pedal.  This  method  requires  less  effort  than  taking  a  running 
start  or  mounting  by  rear  step. 

After  sufficient  momentum  has  been  obtained,  I,  close  the  handle 
bar  ignition  switch,  and  2,  release  the  valve  lifter. 


MOTOR    CYCLES.  465 

While  Riding. — As  soon  as  the  engine  begins  to  operate,  the 
spark  should  be  retarded  and  adjusted  together  with  the  throttle 
to  meet  the  speed  requirements.  On  motor  cycles,  as  a  rule,  the 
speed  is  varied  chiefly  by  the  spark  position.  The  control  of  the 
machine,  at  slow  speeds,  is  made  more  flexible  by  the  use  of  the 
handle  bar  ignition  switch. 


fie.  330. — The  N.  S.  U.  two  speed  transmission  which  Is  attached  to  the 
end  of  which  is  provided  with  a  pinion  engaging  with  a  similar 
pinion  on  the  crank  shaft,  while  to  the  other  end  is  secured  a  bevel 
pinion  engaging  with  a  bevel  wheel  secured  to  the  hub  of  the  back 
wheel.  The  whole  is  enclosed  into  a  gear  case  filled  with  grease 
which  protects  it  against  external  influences  and  ensures  efficient 
lubrication  of  the  parts. 

In  coasting  down  hills,  I,  the  ignition  should  be  cut  out  with 
the  handle  bar  switch,  2,  throttle  closed,  and  3,  exhaust  valves 
lifted,  the  latter  operation,  relieves  the  drag  of  the  engine  and 
admits  fresh  air  to  the  cylinders  which  has  a  tendency  to  keep 
the  spark  plug  points  clean  and  clear  the  cylinder  of  carbon 
deposits. 

In  operating  a  motor  cycle  it  is  important  that  the  lubrication 
of  the  engine  receive  frequent  attention — say  every  ten  miles. 


466 


SELF -PROPELLED  VEHICLES. 


The  crank  case  should  receive  sufficient  oil  that  it  may  splash  up 
against  the  piston  and  cylinder  walls. 

Occasionally  the  crank  case  should  be  drained,  washed  out  with 
gasoline  and  a  fresh  supply  of  oil  provided. 

Stopping. — When  it  is  desired  to  stop:  i,  the  ignition  is  cut 
out  by  the  handle  bar  switch,  2,  exhaust  valves  lifted,  and  3, 
brakes  applied. 

When  leaving  the  machine  the  gasoline  valve  should  be  closed 
and  the  ignition  plug  removed  to  prevent  the  battery  becoming 
exhausted  if  the  machine  stop  with  contact  maker  on  the  spark 
position. 


FIG.  331. — A  coaster  brake  applied  to  the  rear  wheel   of  a  motor  cycle; 
operated  by  a   backward  movement   of   the   pedals. 

Brakes  for  Motor  Cycles. — The  question  of  brakes  is  an  im- 
portant one  with  motor  cycles  and  cannot  be  settled  off  hand 
without  some  consideration  of  conditions. 

In  a  number  of  machines,  the  front  wheel  brake  is  omitted,  and 
the  braking  of  the  rear  wheel  largely  relegated  to  the  compres- 
sion of  the  engine. 

In  the  later  development  of  the  motor  cycle,  the  coaster  form 
of  brake,  incorporated  in  the  rear  hub,  is  the  type  in  general  use. 
An  example  of  this  style  of  brake  is  shown  in  fig.  331. 


CHAPTER  THIRTY-FIVE. 


THE  OPERATION  AND  CONSTRUCTION  OF  STEAM  ENGINES 
FOR  AUTOMOBILES. 

Steam  as  a  Motive  Power. — Vehicles  propelled  by  steam 
possess  certain  advantages  which  are  conceded,  even  by  the  most 
ardent  advocates  of  the  gas  engine.  There  is  a  combination  of 
good  features  inherent  in  steam  propulsion  that  has  met  with 
much  favor. 


FIG.  332.-Diagrams  illustrating  the  "  Lap"  and  "  Lead  "  of  a  Steam  Cylinder  Slide  Valve. 
In  both  sections,  S  and  S  are  the  steam  ports,  and  D  the  exhaust.  The  upper  section 
illustrates  the  "laps"  of  a  valve;  the  space  between  the  lines  C  and  X  giving  the 
"  outside  lap,"  and  between  the  lines  X  and  I  the  "  inside  lap  "  The  lower  section 
illustrates  the  "  lead  "  of  a  valve;  the  space  between  lines  B  and  Y  showing  the  open- 
ing of  the  valve  at  the  beginning  of  the  right-hand  stroke. 

Tt  is  possible  with  steam  to  have  ample  power  together  with  great  over- 
load capacity  without  an  extremely  heavy  plant. 

The  steam  car  as  manufactured  in  America  is  not  a  copy  of  foreign 
ideas,  and  for  some  work  it  has  never  been  approached  by  any  other  form 
of  motive  power.  In  hill  climbing  and  speed  it  is  supreme,  and  the  silence 
m  operation  and  freedom  from  vibration  make  it  very  desirable  when 
maximum  comfort  in  touring  is  desired. 

Among  its  chief  advantages  are  flexibility  and  ease  of  control.  A  steam 
car  may  be  operated  at  any  speed  from  zero  to  maximum.  All  variations 
of  speed  can  be  obtained  without  gear  shifting,  as  it  can  be  easily  varied 
by  changing  the  amounts  of  steam  admitted  to  the  engine.  The  engine  of 

467 


468  SELF-PROPELLED    VEHICLES. 

a  steam  car  can  never  be  stalled  on  account  of  the  absence  of  dead  cen 
tres  and  non-power  strokes,  the  reserve  force  in  the  boiler  and  the  abil- 
ity of  such  a  prime  mover  to  stand  an  overload  of  over  100  per  cent.  This 
enables  one  to  obtain  the  maximum  power  output  under  extraordinary 
conditions.  A  two  cylinder  steam  engine  produces  a  torque  which  can 
only  be  equaled  by  an  eight  cylinder,  four  cycle,  or  a  four  cylinder,  two 
cycle  gas  engine.  Because  of  this  uniform  application  of  energy,  the  wear 
on  tires  is  reduced  to  a  minimum,  and  the  elasticity  of  the  steam  and  free- 
dom from  shock  and  vibration,  reduces  considerably  wear  and  tear  on 
the  entire  mechanism. 

The  improved  methods  of  boiler  construction,  permit  the  use  of  steam 
of  high  pressures  and  of  considerable  degree  of  superheat,  both  of  which 
tend  to  decrease  the  fuel  consumption.  Either  gasoline  or  kerosene  may 
be  used  for  fuel.  The  regulation  of  the  fire  and  feed  water  is  controlled 
by  automatic  devices,  hence,  the  attention  of  the  driver  is  not.  diverted 
from  the  steering  wheel  and  throttle. 


j'i.G.  333.-Diagram  with  a  single  eccentric,  illustrating:  the  position  of  the  steam  valve, 
wiien  the  crank  pin  is  at  the  return  dead  centre,  the  throw  of  the  eccentric  being 
at  an  angle  off  the  perpendicular.  The  arrows  show  the  direction  of  motion. 

The  Slide  Valves  of  a  Steam  Cylinder. — The  mechanism  by 
which  steam  is  admitted  to  the  cylinder  of  a  steam  engine,  con- 
sists of  a  sliding  valve  of  such  a  shape  as  to  open  communication 
from  one  end  of  the  cylinder  to  the  exhaust,  while  the  other  end 
of  the  cylinder  is  receiving  steam  direct  from  the  steam  chest. 
This  will  be  readily  understood  from  the  accompanying  illus- 
tration. There  are  two  kinds  of  valves  in  common  use  on  steam 
carriage  engines ;  the  common  D-valve  shown  herewith,  and  the 
piston  valve,  as  shown  in  a  number  of  engines  hereafter  to  be 
described.  The  object  obtained  by  both  valves  is  the  same,  al- 
though the  piston  valve  is  preferred  by  many  engineers  because 
it  is  better  balanced  in  its  operation,  and  also  because,  owing 
to  its  packing  rings,  it  is  less  liable  to  leakage.  However,  with  a 
well-made  valve  of  either  variety,  the  ends  of  economy  and 
durability  are  equally  maintained. 


THE  STEAM   ENGINE.  469 

The  Operation  of  the  Slide  Valve. — The  valve  controlling  the 
inlet  and  exhaust  ports  of  a  steam  cylinder  is  made  of  such 
length  that,  when  in  mid-position,  it  completely  closes  both 
inlet  ports,  neither  admitting  steam  nor  allowing  it  to  be 
exhausted.  In  the  valve  shown  on  the  accompanying  sec- 
tional cut,  it  is  evident  that,  supposing  it  to  be  moved 
either  to  the  right  or  to  the  left,  the  communication  will  be 
opened  with  the  exhaust  port  on  the  one  side,  sooner  than  with 
the  steam  chest  on  the  other,  thus  permitting  with  a  very  slight 
variation  in  the  length  of  the  stroke,  that  the  exhaust  remain 
open  even  while  the  inlet  of  the  steam  to  the  opposite  face  of  the 
piston  is  cut  off.  In  calculating  the  proportions  of  cylinder  valves 
there  are  two  important,  items  to  be  considered — the  "lap''  and 
the  "lead"  of  the  valves.  The  "lead"  of  a  valve  is  the  amount 
by  which  the  steam  port  is  open  when  the  piston  is  at  the  begin- 
ning of  the  stroke. 

The  lead  may  be  changed  by  varying  the  angular  advance  of  the 
eccentric.  The  "lap"  of  a  valve  indicates  any  portion  added  to  the 
length  of  the  valve,  so  as  to  increase  the  portion  of  the  stroke  dur- 
ing which  the  ports  are  covered,  beyond  that  length  which  is  posi- 
tively required  to  insure  the  closing  of  all  ports  when  the  valve 
is  in  mid-position.  There  are  two  kinds  of  "lap."  The  "outside 
lap"  is  any  portion  added  to  the  length  of  the  valve  beyond  that 
necessary  to  cover  both  inlet  ports  at  mid-position.  The  "in- 
side lap"  is  any  portion  added  to  the  hollow  or  inside  portion  of 
the  D-valve,  over  and  above  what  is  necessary  in  order  to  cover 
the  inner  edges  of  the  steam  ports,  and  to  close  the  exhaust  port 
from  both  sides  when  the  valve  is  in  mid-position.  The  exhaust 
valve  is  closed  somewhat  before  the  completion  of  the  stroke, 
thus  allowing  the  residual  steam  in  the  clearance  to  be  com- 
pressed somewhat  before  the  opening  of  the  inlet.  The  most 
important  result  obtained  in  this  manner  is  that  the  compression 
produces  a  temperature,  as  near  as. possible,  the  same  as  that 
of  the  incoming  steam,  which  is  an  efficient  factor  in  heat 
economy,  although  producing  some  back  pressure  that  slightly 
reduces  the  mean  effective  pressure. 


470 


SELF-PROPELLED    VEHICLES. 


From  the  operations  of  this  valve  and  cylinder,  it  must  be 
evident  that  its  stroke  cannot  be  equal  to  that  of  the  piston  in 
the  main  cylinder.  It  cannot,  therefore,  be  operated  direct  from 
the  crank-shaft  of  the  engine.  Accordingly,  the  most  usual 
method  of  operating  the  steam  valves  of  an  engine  is  by  an 
eccentric  on  the  main  shaft,  which  operates  the  valve  rod.  This 
device  may  be  either  a  single  or  double  eccentric,  according  to 
the  requirements. 

The  Eccentric  Gear  and  Link  Hotion — An  eccentric  is 
a  circular  piece  of  metal,  a  wheel  in  fact,  except  for  the  fact  that 
instead  of  turning  upon  its  centre,  it  is  attached  to  the  shaft  at 


FIG.  334.-Diagram  of  the  Link  Motion  and  Eccentric  Gear  of  a  Steam  Engine.  The  parts 
shown  are:  (1)  backward  eccentric;  (2)  forward  eccentric:  (3-4)  eccentric  rods;  (5) 
slotted  shifting  link;  (6)  link  hanger;  (7)  reversing  arm;  (8)  link  saddle  pin;  (9)  link 
block;  (10)  valve  stem;  (11)  reach  rod.  The  position  shown  in  the  cut  indicates  that 
the  backward  eccentric  is  in  gear  which  gives  a  reverse  motion  to  the  engine. 

a  point  near  its  periphery.  Around  this  disc-shaped  piece  is 
attached  a  circular  metal  strap,  joined  to  a  rod,  which  may  be 
either  attached  direct  to  the  valve  rod,  or,  where  two  eccentrics 
are  used,  to  one  end  of  the  swinging  link.  The  link  is  an  arc- 
shaped  metal  piece,  usually  made  with  a  slot  through  the  greater 
part  of  its  length.  It  is  hung  from  its  centre  point  to  a  link- 
saddle,  which,  as  shown  in  the  accompanying  figure,  is  bolted 
to  either  side  of  the  slot  and  is  suspended  from  the  link  hanger 


THE  STEAM  ENGINE. 


471 


either  above  or  below.  Within  the  slot  is  set  a  link  block,  as 
it  is  called,  so  that  it  may  slide  in  the  slot  through  its  entire 
length,  whenever  the  link  is  raised  or  lowered  on  its  hanger. 
To  this  link  block  is  attached  the  valve  rod.  The  general  ar- 
rangements of  the  link  motion  may  be  understood  from  the 
accompanying  illustration. 

The  Operation  of  the  Shifting  Link — As  already  stated, 
the  link  motion  was  originally  intended  only  for  reversing  the 
engine,  which  is  to  say  to  enable  the  steam  to  be  cut  off  from 


Fio.  335,-Diagram  of  the  Operation  of  the  Link  Motion.  The  centres  of  the  two  eccen- 
trics being  at  4  and  8,  the  crank  pin  at  2,  the  link  at  mid-gear,  the  eccentric  rods 
will  be  indicated  by  the  full  lines,  4-6,  8-10.  When  the  crank  pin  is  at  1,  the  centres 
of  the  eccentrics  will  be  at  3  and  7,  and  the  positions  of  the  rods  on  the  dotted  lines, 
3-5  and  7-9.  The  distance,  D,  indicates  the  vertical  distance  between  the  centres  of 
the  eccentrics  in  the  full  and  dotted-line  positions.  If  from  the  centre,  8,  with  the 
rod  as  the  radius,  an  arc  be  drawn  to  F,  the  distance,  C,  shows  the  position  of  the  link 
if  both  rods  were  "  open  "  with  the  crank  at  the  cylinder  end,  2,  instead  of  at  the  op- 
posite dead  centre,  1.  The  distance,  C,  is  equal  to  the  distance,  E,  and  the  total  dis- 
tance (D  +  E)  that  the  valve  moves  is  twice  the  lap,  plus  twice  the  lead,  plus  the 
distance,  or  angularity,  occasioned  by  the  rods  being  crossed,  when  the  crank  is  on 
the  cylinder  end  dead  centre,  2,  becoming  opened  when  the  crank  is  at  dead  centre,  1. 


one  side  of  the  cylinder  and  admitted  to  the  other,  whenever  de- 
sired, by  shifting  the  motion  of  the  slide  valve.  In  addition  to 
this  function,  however,  the  link  motion  provides  a  means  for 
using  the  steam  expansively,  when  cutting  off  the  supply  of  live 
steam  at  any  earlier  point  in  the  piston  stroke,  which  act  is  ac- 
complished by  reducing  the  travel  of  the  slide  valve.  When 
the  link  block  is  at  one  end  of  the  slot,  the  valve  receives  the 
motion  of  the  eccentric  rod  attached  to  that  end  of  the  link,  and, 
consequently,  since  the  links  are  set  at  angles  somewhat  greater 
than  1 80  degrees,  the  one  is  for  the  forward  motion  of  the  en- 


i72  SELF-PROPELLED    VEHICLES. 

gtne,  the  other  for  the  reversed  motion.  In  the  accompanying 
illustration,  the  backward  eccentric  is  in  gear.  By  this  means, 
whenever  the  link  is  shifted,  only  the  eccentric  whose  rod  stands 
opposite  the  link-block  imparts  its  motion  to  the  valve.  The 
other  is  practically  inactive,  except  for  imparting  a  slight  oscil- 
latory motion  to  the  link,  which  in  general  practice  is  negligible. 
The  link  which  is  in  gear  acts,  in  reality,  like  a  short-throw 
crank,  or  as  if  it  were  a  single  eccentric.  From  the  position  of 
"full-gear" — that  is,  when  the  link-block  stands  at  either  end  of 
the  slot — the  travel  of  the  valve  may  be  more  or  less  modified 
until  the  centre  point  of  the  slot  is  reached,  which  point  is  called 


5*ic.  336. — View  of  the  Stanley  engine  with  cylinders  cut  away,  to  show 
piston  and  valve  motion.  In  the  position  shown,  one  valve  is  be- 
ginning- to  open  to  admit  steam  to  the  cylinder;  the  other  valve  has 
passed  the  point  of  cut  off,  the  opposite  cylinder  end  being  in  com- 
munication with  the  exhaust  passage.  The  valves  of  the  Stanley 
engine  are  operated  by  the  familiar  Stevenson  link  motion. 

mid-gear.  There  the  travel  in  either  direction  is  so  slight  that 
the  steam  and  exhaust  ports  of  the  cylinder  are  not  opened.  This 
is  in  reality  the  "dead  point,"  and  further  shifting  of  the  link 
in  the  same  direction  begins  the  process  of  reversing  by  increas- 
ing the  travel  of  the  valve  in  the  opposite  direction.  When  at 
mid-gear  the  valve  partakes  of  the  motion  of  both  eccentrics 
equally,  but  since  their  motions  describe  a  cassinian,  or  flattened 
figure  8,  laid  on  its  side,  of  which  the  link-block  is  the  centre,  the 
motion  is  at  its  point 


THE   STEAM   ENGINE. 


473 


When  the  link  is  at  full  gear,  the  travel  of  the  valve  equals 
the  throw  of  the  eccentric,  less  the  angularity  of  the  eccen- 
tric rod.  When  the  link  is  at  mid-gear,  the  travel  of  the 
valve  is  equal  to  twice  the  lap  and  lead  of  the  valve,  plus  twice 
the  angularity  of  the  eccentric  rods.  By  the  angularity  of  the 


Grossed    PocLs 


Fio.  3  3  7.-Diagram  showing  the  positions  of  the  eccentric  throws  and  rods  at  full  gear 
and  mid-gear,  when  the  rods  are  "open  "  and  "crossed  "  with  the  crank  at  the  for- 
ward dead  centre,  marked  1  in  the  previous  cut. 

eccentric  rods  is  meant  the  distance  the  centre  of  the  link  or  the 
valve  would  move,  should  the  rod  of  the  geared  eccentric  be 
disconnected  from  it  and  connected  with  the  other  link.  The 
amount  of  the  angularity  thus,  of  course,  varies  with  the  length 
of  the  rods.  The  shorter  the  rods,  the  greater  the  travel  of  the 


474 


SELF-PROPELLED   VEHICLES. 


valve,  owing  to  the  crossing  of  the  rods  during  a  one-half  revo- 
Jution  of  the  crank.  When  the  eccentric  rods  of  a  direct  con- 
nected link  motion  are  disposed  as  shown  in  the  accompanying 
diagram,  and  the  link  motion  and  gear  of  the  crank  is  at  the 


FIG.  338. — Diagram  illustrating1  the  principles  of  the  Joy  valve  g-ear. 
Motion  is  communicated  to  the  valve  by  a  system  of  levers  operated 
by  the  connecting  rod.  The  advantages  secured  by  the  use  of  the 
Joy  valve  gear  are,  quick  admission  and  cut  off,  and  constant  lead 
for  all  degrees  of  expansion. 

dead  point  marked  i,  the  rods  are  said  to  be  open.  If  they  are 
disposed  as  shown  by  the  dotted  lines  in  the  same  figure,  and 
the  crank  is  at  the  dead  point,  2,  they  are  said  to  be  crossed. 
Open  rods  give  an  increasing  lead  from  full  gear  towards  mid- 
gear,  while  crossed  rods,  give  a  decreasing  lead. 


THE  STEAM  ENGINE. 


475 


The  Joy  Valve  Gear. — This  form  of  valve  gear  derives  its 
motion  from  an  arm  attached  to  the  connecting  rod  near  the 
wrist  pin.  The  link  is  pivoted  at  its  upper  end  and  by  moving  it 
forward  or  backward  from  the  central  position,  the  cut  off  can 
be  regulated. 


73- 


FIG.  339.— The  Joy  Valve  gear  as  applied  to  the  White  engine.  The  valve 
gear  parts  are:  74,  valve;  73,  valve  stem;  58,  valve  crosshead;  61, 
valve  gear  levers;  72,  valve  slide  rollers.  The  other  details  shown 
are:  48,  piston:  59,  piston  rod;  75,  crosshead;  76,  wrist  pin;  77,  con- 
necting rod;  27,  lever  for  operating  the  pumps. 


476  SELF-PROPELLED   VEHICLES. 

This  type  of  valve  gear,  is  shown  in  the  diagram  fig.  338. 

The  valve  rod  V  is  operated  by  the  lever  A.  There  is  a  block 
B,  provided  with  a  curved  slot  is  used,  in  which  the  pin  forming 
the  fulcrum  of  the  lever  A  slides. 

The  motion  is  imparted  to  the  lever  A  directly  from  the  con- 
necting rod  by  means  of  the  connecting  link  C,  one  end  of  which 
is  pivoted  to  the  connecting  rod,  the  other  end  to  the  suspension 
link  D. 


FIG.  840. — View  of  the  Stanley  engine,  showing  uiain  hearing,  spur  gear,  eccentrics,  link 
motion  and  "hooking  up"  device.  These  engines  are  made  in  three  sizes:  3x4;  4x5; 
and  4J  x  6J.  The  horsepower  rating  for  the  several  sizes  is  ten,  twenty,  and  thirty, 
respectively. 

The  vertical  motion  of  the  connecting  link  moves  the  valve  an 
amount  equal  to  its  lap  and  lead,  while  the  horizontal  motion 
causes  the  ports  to  open  their  full  opening,  by  moving  the  ful- 
crum up  and  down  in  the  inclined  slot. 

By  means  of  the  reversing  lever  L  the  incline  of  the  block  B 
can  be  altered,  or  reversed,  to  reverse  the  engine. 

The  diagram  fig.  338  is  intended  simply  to  illustrate  the  prin- 
ciple of  the  valve  gear,  the  engine  shown  being  of  the  marine 
type.  The  Joy  valve  gear  has  been  adopted  by  the  White  Com- 
pany and  its  application  to  the  White  engine  is  shown  in  figs.  339 
and  347. 


THE  STEAM  ENGINE.  47T, 

A  feature  of  this  valve  gear  is  that  it  gives  a  rapid  motion  tP 
the  valve  when  opening  and  closing,  thus  producing  a  quick  ad- 
mission and  cut  off.  It  gives  a  constant  lead  for  different  cut 
offs,  and  a  compression  more  nearly  constant  than  that  produced 
with  the  Stevenson  link  motion. 

The  Joy  gear  while  having  many  good  features  has  numerous 
joints  which  are  subject  to  wear. 

The  Serpollet  Single-Acting  Engines. — In  the  effort  to  sim- 
plify, as  far  as  possible,  the  construction  and  operation  of  steam 
vehicle  motors,  intended  for  use  on  light  carriages,  several  in- 
ventors have  contrived  excellent  types  of  single-acting  engines. 
Among  the  advantages  to  be  derived  from  the  use  of  this  type 
of  motor,  we  may  mention  dispensing  with  the  stuffing-box  and 
several  other  constructions,  which  involves  constant  danger  of 
wear  and  difficulty  or  repair.  The  Serpollet  steam  engine  very 
much  resembles  some  types  of  gasoline  motors  used  on  heavy 
vehicles,  both  as  regards  the  cylinder  and  piston  and  operation 
of  the  valves.  The  cylinders  are  horizontal,  of  the  double  opposed 
type. 

The  piston  is  of  the  trunk  type,  consisting  of  a  somewhat 
elongated  hollow  cylinder,  with  the  crank  rod  pivoted  on  the 
gudgeon  pin  somewhat  less  than  midway  in  its  length.  The 
valves  in  this  engine  are  of  the  familiar  mushroom  or  poppet 
type,  and  are  opened  by  a  push  rod  positively  operated  from  a 
cam  shaft.  This  shaft  is  operated  by  a  spur-wheel,  which  meshes 
with  another  spur  of  the  same  diameter,  mounted  on  the  crank- 
shaft, so  that  the  two  turn  in  even  rotation.  The  exhaust  valves 
are  of  precisely  similar  construction  and  are  also  positively  oper- 
ated from  the  same  cam-shaft. 

Such  an  engine  as  this  has  been  constructed  with  from  two  to 
six  cylinders,  and  as  may  be  understood,  gives  about  the  same 
power  effect  as  an  engine  of  the  ordinary  design  and  same  pro- 
portions of  stroke,  having  from  one  to  three  cylinders.  The  cyl- 
inders operate  on  one  plane,  and  are  not  offset,  as  in  many  op- 
posed-cylinder gasoline  motors.  The  steam  and  exhaust  valves 
are  positively  operated  by  a  series  of  cams  on  a  shaft,  so  that 
when  the  steam  valve  of  one  is  open,  its  exhaust  is  closed,  in- 


473 


SELF-PROPELLED    VEHICLES. 


volving  that  the  steam  valve  of  the  opposite  cylinder  is  closed 
and  its  exhaust  open.  In  order  therefore  to  reverse  the  engine, 
it  is  necessary  only  to  slide  the  row  of  cams  on  the  square  cam- 
shaft that  carries  them,  so  as  to  shift  the  positions  and  operation 
of  the  valves  on  the  two  cylinders. 

The  Piston  of  a  Steam  Engine — The  piston  of  a  steam  engine, 
as  shown  in  an  accompanying  figure,  usually  consists  of  a  flat- 
tened cylindrical  piece  of  slightly  smaller  diameter  than  the  bore 
of  the  cylinder,  in  which  it  slides.  Steam-tight  contact  is  ob- 
tained by  springing  packing  rings  into  grooves  cut  in  its  cir- 
cumference. The  accompanying  cut  shows  three  such  rings 
sprung  on  the  piston.  The  steam  admitted  through  the  inlet 
valve  bears  upon  one  face  of  the  piston,  and  by  its  expansive 
energy  causes  the  piston  to  move. 


Flo.  341.— The  Piston  of  a  small  double-acting  steam  engine,  showing  method  of  connect- 
ing the  piston  rod,  and  the  position  of  the  packing  rings.  The  parts  are:  o,  a,  the 
body  of  the  piston;  b,  6,  the  circumference  bearing  the  packing  rings;  c,  c,  the  cen- 
tral boss  receiving  the  coned  end  of  the  rod. 

The  Practical  Expansion  Ratio  for  Steam. — In  the  practical 
operation  of  the  steam  engine,  as  most  generally  understood, 
the  steam  is  fed  direct  from  the  boiler  to  the  cylinder,  there  ex- 
panding from  its  original  pressure  to  a  number  of  volumes,  pro- 
portioned to  the  length  of  the  stroke  and  point  of  cut-off.  The 
idea  of  cutting  off  the  supply  of  steam  before  the  completion  of 
the  stroke,  and  making  use  of  its  expansive  energy  during  the 
remaining  portion,  constitutes,  as  we  have  seen,  the  first  im- 
provement made  by  Watt.  According  to  Boyle's  Law,  already 
quoted,  the  pressure  of  the  steam  is  in  exactly  inverse  ratio  to 


THE  STEAM  ENGINE.  479 

its  expansion,  which  is  to  say  that  when  a  body  of  steam  is  ex- 
panded to  twice  its  original  volume,  it  should  have  just  one-half 
its  original  pressure,  so  long  as  the  temperature  be  constant. 
This  law  is  never  exactly  followed  in  practice,  the  general  rule, 
as  shown  by  indicator  diagrams,  being  a  rapid  fall  during  the 
first  period  of  expansion  and  a  more  gradual  one  in  the  latter 


FIG.  342. — The  Ofeldt  compound  engine.  The  cylinders  are  cast  in  one  piece  and  are 
bolted  to  one  end  of  the  oil  box.  They  are  2\  and  4,  with  four-inch  stroke,  and  the 
valve  chests  are  located  at  each  side.  The  steam  enters  the  H.  P.  valve  chest  through 
a  i  inch  connection  in  the  center  of  the  valve  chest  cover,  and  exhausts  around  the 
cylinders  to  the  L.  P.  valve  chest.  The  steam  exhausts  through  a  $  inch  connection 
at  corner  of  valve  cheat  on  end  of  cylinder.  The  reverse  motion  is  of  the  special 
type,  only  one  eccentric  being  required  for  each  valve.  The  reverse  is  set  at  the  end 
of  the  crank  shaft  and  extends  out  through  the  side  of  the  oil  box,  where  it  is  con- 
nected to  a  small  gear  wheel.  In  either  the  forward  or  backward  motion  the  reverse 
is  held  in  place  by  the  crank  shaft.  The  engine  can  be  reversed  when  in  motion 
without  closing  the  throttle.  Feed  water  pump  is  provided  operated  by  an  eccentric 
on  the  shaft.  A  simpljng  connection  for  starting  is  made  on  top  of  the  H.  P.  cylinder. 
The  valves  are  the  sliding  or  D  tvpe.  The  engine  runs  in  oil  and  is  rated  at  fifteen 
horsepower,  a  larger  size  3  J  and  6  i  by  5  is  rated  at  thirty  horsepower. 


480 


SELF-PRO  PULLED    VEHICLES. 


period.  However,  for  general  purposes,  the  law  is  assumed  to 
be  perfectly  operative,  and  the  rule  for  calculating  the  pressure 
at  any  point  of  expansion,  is  to  divide  the  original  absolute  pres- 
sure by  the  number  of  times  it  has  expanded.  Thus,  steam  fed 
to  a  cylinder  at  100  pounds  gauge,  or  115  pounds  absolute,  has 
a  pressure  of  57^  pounds  when  expanded  to  two  volumes,  a 
pressure  of  38  1-3  pounds  when  expanded  to  three  volumes  and 
n  pressure  of  28f  pounds  when  expanded  to  four  volumes. 


FIG.  343.  —  The  MacLachlan  single  acting  compound  steam  engine.  It  has 
six  cylinders,  three  3"  high  pressure  and  three  6"  low  pressure 
with  3^"  stroke  and  is  rated  at  30  H.  P.  with  300  Ibs.  steam  and 
600  revolutions.  The  valves  are  of  the  poppet  type  and  the  valve 
gear  is  such  that  steam  may  be  cut  off  at  any  point  of  the  stroke 
down  to  three-fourths.  One  lever  controls  the  entire  operation  — 
simpling,  compounding,  reversing,  starting  and  the  variable  cut  off. 

The  following  table  gives  the  theoretical  efficiency  of  steam 
cut  off  at  various  other  points  of  the  stroke: 

Cutting  off  at  -j^j-  stroke  increases  efficiency  3.3  times. 

"        %         ««  "  •••  3.07     " 

"      ^        «  "  "  2.6       " 

"       £         "  "  2.39     " 

"  fV  "  "  2.2  " 

"  |  «  "                         «  1.98  " 

»  A  "  "  I.92  » 

"  £  "  "                       "  1.69  " 


,<  „  „      I47   .. 

„    ^     ..         ..  .,      I-35   , 

•  I  <«          £  «.  ««  I>29       " 

In  the  steam  engine,  these  values  are  considerably  reduced  on  account 
of  losses  due  to  radiation,  condensation,  leakage,  etc.  In  horse  power 
calculations,  therefore,  the  theoretical  mean  effective  pressure  is  multi- 
plied by  a  coefficient  or  diagram  factor  as  it  is  called  which  varies  for 
different  classes  of  engines  from  .6  to  .9  as  has  been  determined  by  nu- 
merous tests. 


THE   STEAM   ENGINE. 


481 


FIG.  344. — The  Lane  engine.  This  is  a  cross  compound  with  steam 
chests  adjacent  to  each  other.  Both  cylinders  have  slide  valves 
and  the  pistons  are  provided  with  two  snap  rings  each.  The  valve 
gear  consists  of  the  Stevenson  link  motion.  The  Lane  engine  is 
built  in  two  sizes:  3*4  and  B1^  by  3%;  3%  and  6%  by  4.  They  are 
rated  at  twenty  and  thirty  horsepower,  respectively. 


PIG.  345. — Showing  simpling  valve  on  back  of  the  Lane  engine.  It  con- 
sists of  a  small  cylinder  having  ports  connecting  directly  with  the 
high  pressure  exhaust,  the  high  and  low  pressure  steam  chests,  and 
the  free  exhaust.  There  is  a  one-piece  plug  valve  having  proper 
passages  through  it,  and  arranged  so  that  the  different  rotative  posi- 
tions effect  the  chaneres  of  ports  for  converting  the  engine  from 
compound  (using:  steam  first  in  small,  and  afterward  in  the  large 
cylinder)  to  single  expansion  (using  high  pressure  directly  in  both 
cylinders). 


482 


SELF-PROPELLED    VEHICLES. 


On  Compounding:  a  Steam  Engine. — A  compound  engine 
is  one  in  which  the  steam  is  used  several  times  over  in  as  many 
separate  cylinders,  although  usually  applied  to  engines  operating 
with  two  cylinders.  The  steam  is  fed  from  the  boiler  direct  to 
the  first  cylinder,  in  which  it  is  cut  off  early  in  stroke,  in  order  that 
its  expansion  may  be  utilized  to  the  greatest  possible  extent.  The 
exhaust  from  this  cylinder  is  then  fed  into  the  second  cylinder, 
generally  two  or  three  times  the  cubic  contents  of  the  first,  and 
is  worked  expansively  to  a  point  as  near  atmospheric  pressure 
as  possible.  The  most  practical  and  efficient  application  of  this 


FIG.  34  6.— Diagram  of  a  "  Cross  Compound  "  Steam  Engine.  The  cranks,  C  and  C,  are  at 
90°.  The  high-pressure  steam  port  is  at  3;  the  H.  P.  exhaust  to  L.  P.  cylinder  at  R, 
and  the  exhaust  to  atmosphere  from  the  low-pressure  cylinder,  at  E. 

principle  is  in  the  triple  and  quadruple  expansion  engines,  so 
largely  used  in  marine  work,  which,  in  connection  with  the 
vacuum-producing  condenser,  allows  the  steam  to  be  worked 
from  the  highest  available  pressure  down  to  near  zero. 
There  are  two  common  forms  of  compound  engines  of  two  or 
three  cylinders,  which  from  the  arrangements  of  the  working 
parts,  are  known  as  "tandem-compound"  and  cross-compound." 
In  the  tandem-compound  engine,  the  cylinders  are  placed  end 
to  end,  the  two  pistons  operating  one  piston  rod.  In  the 


THE   STEAM   ENGINE. 


483 


FIGS.  347  and  348. — The  White  Engine  and  sectional  view  of  "simpling 
valves."  The  engine  is  a  double  acting  compound  fitted  with  the 
Joy  valve  gear  (61,  71  and  72),  and  is  built  in  two  sizes:  2^  and 
4%  by  3,  also  3  and  5  by  4%.  The  power  rating  is  twenty  and 
forty  horsepower  respectively.  The  simpling  valves  (12  and  14)  are 
used  in  starting  to  admit  live  steam  to  the  low  pressure  cylinder 
in  case  the  high  pressure  piston  be  on  the  dead  centre.  There  are 
two  pumps  operated  by  the  engine,  an  air  pump  67,  and  the  con- 
denser pump  39. 


484  SELF-PROPELLED    VEHICLES. 

cross-compound  engine  the  cylinders  are  placed  side  by  side, 
the  two  piston  rods  operating  on  a  single  crank-shaft.  The  latter 
model  is  that  most  frequently  used  in  compounding  steam  engines 
for  motor  vehicles. 

Compound  5team  Engines  for  Light  Carriages. — Although 
many  of  the  earliest  types  of  the  American  steam  carriage  still 
use  simple  engines,  several  of  the  most  excellent  of  the  later  pat- 
terns have  adopted  compound  engines.  The  principal  objection 
made  by  many  authorities  to  the  use  of  compound  engines  on 
steam  road  carriages  of  light  weight  is  that  with  cylinders  of 
average  dimensions,  working  pressure  of  between  150  and  200 
pounds,  in  the  high  pressure  cylinder,  and  a  cut-off  generally 
between  ^  and  f  stroke,  which  has  been  found  most  economical 
under  ordinary  conditions,  the  low  pressure  cylinder  would  be 
doing  little  or  no  work,  the  whole  strain  of  operation  coming  on 
the  former,  which  would  practically  be  working  against  a 
vacuum. 

A  maker  of  steam  carriage  engines  states,  that  in  order  to 
obtain  effective  work  from  both  cylinders  of  a  compound  en- 
gine, the  high  pressure  cylinder  must  be  made  about  one-half 
the  size  of  the  cylinder  used  in  the  simple  engine.  Then,  he  as- 
serts, the  mean  pressure  will  range  from  75  to  100  pounds  in  the 
usual  running,  with  cut-off  at  f  stroke  and  the  diameters  of  the 
two  cylinders  in  ratio  of  i  to  3,  and  the  low  pressure  cylinder  will 
do  its  share  of  the  work,  with  the  desired  economy  of  power. 
The  difficulty  claimed  with  this  arrangement  is,  that  the  total 
reserve  power  will  then  be  only  about  one-half  that  of  the  sim- 
ple engine,  unless  boiler  steam  can  be  admitted  to  both  cylin- 
ders at  any  desired  time  while  running,  as  well  as  in  starting,  and 
the  back-pressure  be  eliminated  by  exhausting  from  both  to  at- 
mosphere. 

The  higher  boiler  pressures,  made  available  through  improved 
construction  is  very  favorable  to  the  use  of  compound  engines, 
permitting  a  greater  expansion  range  and  more  economical  work- 
ing. 


CHAPTER  THIRTY-SIX. 


BOILERS  AND  FLASH  GENERATORS. 

Small  Shell  Boilers  for  Carriages. — Many  of  the  best  known 
makes  of  American  steam  carriage  have  vertical  fire  tube  shell 
boilers.  All  such  boilers  are  of  small  dimensions,  with  a  con- 
sequently small  water  capacity.  But  they  have  a  very  extensive 
heating  surface,  owing1  to  the  insertion  of  a  large  number  of  fire 


I'IG.  349. — Shell  Boiler,  with  flange  connections  for  the  tube  plates.  The 
shell  is  strengthened  by  winding  several  layers  of  steel  piano  wire 
around  the  length  of  the  boiler.  This  cut  gives  a  section  on  the 
centre,  showing  one  row  of  tubes.  These  are  usually  made  of 
copper  which  possesses  a  superior  heat  conducting  property. 

tubes  and,  according  to  many  showings,  seem  capable  of  generat- 
ing a  power  pressure  far  in  excess  of  the  usual  rule  of  proportions 
for  surface. 

The  shells  are  constructed  of  seamless  steel,  formed  up  or 
drawn  out  of  solid  pieces  of  the  best  quality  of  metal,  and  by  the 
same  method  used  in  making  tanks  for  soda  fountains,  oxygen- 
gas  outfits,  carbon-dioxide  machines,  etc.,  many  of  which  are 
tested  up  to  3,000,  4,000  and  5,000  pounds  per  square  inch.  A 
wall  section  of  steel  made  in  that  way  three-sixteenths  of  an  inch 

485 


486  SELF-PROPELLED    VEHICLES. 

thick  and  having  the  form  of  a  cylinder  twenty  inches  in  diameter, 
withstands  a  pressure  of  more  than  fifteen  hundred  pounds  per 
square  inch. 

In  order  to  get  a  large  heating  surface  in  a  shell  of  small-  di- 
ameter, the  tubes  are  placed  very  close  together  and  there  are 
a  great  number  of  them  as  shown  in  fig.  350,  hence,  the  boiler 
heads  are  strengthened  in  such  a  way  that  they  are  even  stronger 
than  the  shell. 


FIG.  350. — The  Stanley  fire  tube  boiler.  The  shell  and  lower  head  are  of 
one  piece  of  pressed  steel.  The  bands,  as  shown  in  the  cut  are  of 
thin  brass,  to  hold  the  asbestos  covering  in  place. 

It  is  claimed  by  a  well-known  builder  of  automobile  boilers  that  it  is 
impossible  to  explode  a  boiler  as  constructed  for  an  automobile,  since  ac- 
cording to  their  tests,  the  tubes  will  flatten  at  a  pressure  of  ten  hundred 
pounds  and  then  leak  gradually  until  the  pressure  falls,  without  doing 
other  damage. 

The  fire  tube  boiler  used  in  the  Stanley  car  has  a  shell  slightly 
different  from  the  ordinary  construction.  It  is  of  the  same  type 


BOILERS  AND  FLASH  GENERATORS. 


487 


as  originally  used  on  the  Locomobile  Steamers  and  is  shown  in 
fig-.  350.  The  shell  which  is  of  seamless  pressed  steel,  is  reinforced 
by  two  layers  of  piano  wire  wound  around  its  exterior  under 
tension.  The  lower  head  is  part  of  the  pressed  steel  shell.  The 
tubes  are  33/64  inch  outside  diameter  and  are  expanded  into  the 
heads  by  means  of  a  taper  expander,  shown  in  fig.  351.  All  tubes 
are  14  inches  long,  excepting  those  in  the  26  inch  boilers  which 
are  16  inches  long.  In  the  18  inch  boilers  there  are  469  tubes 
with  66  square  feet  of  heating  surface.  In  the  23  inch  boilers 
there  are  751  tubes  with  104  square  feet  of  heating  surface.  In 
the  26  inch  boilers  there  are  999  tubes  with  158  square  feet  of 
heating  surface. 


FIG.  351. — Roller  tube  expander  for  expanding-  tubes  of  boilers  and 
burners.  In  expanding  a  tube,  the  roller  end  is  inserted  in  the  tube 
and  the  central  tapered  pin  turned  with  an  inward  pressure.  The 
action  of  the  pin  Dresses  the  rollers  against  the  tube  with  great 
force,  thus  expanding  the  latter  and  making  a  tight  joint. 

As  usually  constructed,  the  tubes  in  shell  boilers  are  spaced 
the  same  distance  apart,  the  distance  betwen  the  outside  edges 
of  the  tubes  being  only  one-quarter  of  an  inch.  It  will  be  seen 
from  the  dimensions  of  the  Stanley  boilers  given  above,  that  a 
large  heating  surface  is  obtained  with  small  diameter  of  shell. 
Since  the  tubes  are  quite  short,  the  entire  heating  surface  is  in 
close  proximity  to  the  fire  and  hence  very  effective. 

Of  Tubular  Boilers  in  General. — The  wide  use  of  tubular 
boilers  in  steam  carriages  and  for  other  purposes  is  explained 
by  the  fact  that  in  its  use  the  problem  of  how  best  to  control 
the  circulation,  to  the  ends  of  quick  steaming  and  higher  dura- 
bility, through  more  uniform  distribution  of  heat,  has  been  best 
solved.  Although  very  many  varieties  of  tubular  boiler  possess 


488 


SELF-PROPELLED    VEHICLES. 


high  efficiency  as  generators  of  steam,  none  of  them  attain  such 
great  power  for  absorbing  heat  but  what  there  is  still  room  for 
efforts  to  discover  some  means  of  neutralizing  waste  in  this 
particular. 

Small  boilers  with  seamless  drawn  shells  for  automobiles  are 
now  manufactured  in  a  number  of  sizes,  the  standard  dimensions 
and  horse  power  ratings  are  as  follows : 

AUTOMOBILE  BOILERS. 

(Seamless  Shells.) 


Internal 
Diam.  In. 

Thickness 
of  Shells 
In. 

Number  of 
J  inch  Tubes. 

Length  of 
Tubes  In. 

Actual  Horse 
Power. 

Approximate 
Weight  in 
Pounds. 

14 

& 

309 

131 

4ft 

112 

16 

A 

420 

131 

5A 

146 

16 

420 

134 

5$ 

154 

17 

A 

480 

13| 

6* 

158 

17 

1 

480 

131 

6ft 

174 

18 

A 

529 

131 

7A 

180 

18 

1 

529 

131 

7* 

196 

19 

T8ff 

586 

13 

8ft 

203 

19 

\ 

586 

13^ 

81% 

222 

20 

A 

676 

13J 

10* 

231 

20 

676 

13^ 

10$ 

257 

20 

676 

I* 

lift 

272 

20 

676 

15} 

12& 

287 

20 

676 

16J 

r 

13 

302 

23 

850 

13j 

12 

293 

23 

850 

U\ 

13 

312 

23 

1 

850 

15J 

14 

331 

23 

i 

850 

16 

1*A 

350 

The  sixteen,  seventeen,  eighteen  and  nineteen-inch  boilers  listed  above 
are  made  with  tubes  fourteen,  fifteen,  sixteen  seventeen  and  eighteen 
inches  long,  which  approximately  increases  the  horse  power  in  proportion 
as  the  tubes  increase  in  length. 

Heavy  Truck  Boilers. — Fire  tube  boilers  suitable  for  com- 
mercial vehicles  differ  from  the  automobile  type,  only  in  that  both 
heads  are  riveted  in,  and  that  the  shell  is  made  from  heavier 
stock.  The  shells  are  not  seamless  drawn,  but  are  welded  by  an 
electrical  process  making  them  homogenous  and  uniform 
throughout.  Truck  boilers  are  usually  made  with  an  extended 
shell  which  projects  a  few  inches  below  the  crown  sheet  to  form 
a  casing  for  the  burner.  It  is,  therefore,  necessary  to  cut  holes 


BOILERS  AND  FLASH  GENERATORS. 


489 


through  the  side  of  the  shell  to  accommodate  mixing-  tubes  and 
other  burner  pipes.  Heavy  truck  boilers  with  welded  shells  are 
regularly  manufactured  in  various  sizes  as  follows: 

HEAVY  TRUCK  BOILERS. 

(Welded  Shells.) 


Internal 
Diam.  In. 

Thickness 
of  Shells 
In. 

Number  of 
J  inch  Tubes. 

Length  of 
Tubes  In. 

Actual  Horse 
Power. 

Approximate 
Weight  in 
Pounds. 

22 

TB* 

825 

13i 

Hy'ff 

332 

22 

A 

825 

16 

1*A 

354 

22 

A 

825 

20 

17A 

390 

23 

A 

850 

18 

16  & 

384 

23 

X 

850 

22 

19A 

420 

23 

A 

850 

23 

20* 

464 

24 

ft 

951 

13 

»A 

365 

24 

A 

951 

16 

16T6ff 

433 

24 

A 

951 

18 

18T7ff 

472 

24 

T6, 

951 

20 

20& 

525 

24 

A 

951 

22 

22& 

566 

24 

A 

951 

23 

23A 

590 

24 

A 

951 

24 

24A 

608 

24 

A 

951 

26 

28 

659 

24 

A 

951 

28 

29 

700 

24 

A 

951 

30 

31  rV 

742 

28 

A 

1320 

16 

23 

675 

28 

A 

1320 

20 

28A 

844 

30 

& 

1470 

16 

25^ 

850 

30 

A 

1470 

20 

32A 

890 

Boiler  Tubes. — In  the  construction  of  shell  boilers  the  tubes 
are  made,  either  of  steel  plated  with  copper  or  zinc,  or  of  seamless 
drawn  copper. 

In  boiler  construction,  copper  is  superior  to  steel  from  the  fact 
that  it  has  a  much  higher  thermal  conductivity,  involving  con- 
siderably smaller  loss  of  heat  in  proportion  to  its  exposed  surface. 

The  relative  heat  conducting  power  of  copper  and  steel  is  such  that 
one  square  foot  of  copper  heating  surface  is  as  efficient  as  2.13  square 
feet  of  steel  heating  surface.  The  choice  of  steel  or  copper  tubes,  there- 
fore will  depend  in  part  on  the  boiler  efficiency  desired. 

The  working  pressure  to  be  carried,  also  governs  the  choice 
between  copper  and  steel  for  tubes.  Copper  more  easily  resists 
the  chemical  action  of  impure  water. 


490 


SELF-PROPELLED    VEHICLES. 


Advantages  of  Controlling  Circulation. — By  providing  suit- 
able arrangements  for  directing  the  rising  and  falling  cur- 
rents, so  that  interference  is  obviated,  a  very  desirable  end 
is  attained — chemical  impurities,  held  in  solution  by  the  water, 
and  precipitated  so  as  to  form  scale  deposits,  when  it  is  evapo- 
rated, are  prevented  from  locating  and  hardening ;  being  received 
into  mud  drums  suitably  arranged  at  the  lowest  point  of  the 
water  chamber,  where  they  can  be  conveniently  removed. 


FIG.  352.— The  Thornycroft  Steam  Wagon  Boiler. 

According  to  statistics  furnished  by  various  authorities  these  scale  d1?- 
posits,  consisting  mostly  of  lime  and  other  non-conducting  substances, 
interfere  with  the  heat-conducting  properties  of  the  metal  to  an  enormous 
extent.  A  deposit  of  1-16  inch  involving  a  loss  of  13  per  cent,  of  the  fuel ; 
a  deposit  of  %  inch,  a  loss  of  25  per  cent. ;  a  deposit  of  ]4  inch,  a  loss  of 
38  per  cent. ;  a  deposit  of  V?.  inch,  a  loss  of  60  per  cent.  The  result  of 
allowing  such  incrustations  to  increase  will  be  inevitably  that  the  metal 
surface  exposed  to  the  fire  is  burned  out  and  the  boiler  ruined. 


BOILERS  AND  FLASH  GENERATORS.  491 

Water  Tube  Boilers. — A  water  tube  boiler,  consists  essentially 
of,  i,  a  drum  in  which  is  contained  both  the  water  and  steam.  In 
construction  this  drum  may  be  either  vertical  or  horizontal.  A 
vertical  drum  is  sometimes  spoken  of  as  a  stand  pipe.  In  sizes 
suitable  for  automobiles,  the  drum  is  from  about  five  to  eight 
inches  in  diameter. 

In  addition  to  the  drum  there  is,  2,  a  series  of  pipes  or  coils. 
In  the  case  of  a  vertical  drum,  one  end  of  each  coil  is  connected 
to  the  lower  end  of  the  drum  and  the  other  end  of  the  coil,  to  the 
upper  part  of  the  drum.  These  coils  or  pipes  are  called  the  up- 
flow  coils  or  risers,  because  the  circulation  of  the  water  through 
them  is  upward. 

The  reason  for  this  is  that  water  expands  as  its  temperature  increases, 
and  consequently,  its  weight  per  unit  volume  is  diminished.  Hence,  the 
water  in  the  drum  being  of  lower  temperature  than  that  in  the  coils,  has 
a  greater  density  and  therefore  causes  the  water  to  rise  in  the  coils. 

In  water  tube  boilers  having  horizontal  drums,  a  down  flow 
pipe  is  necessary.  The  upper  ends  of  the  coils  are  connected  to 
the  drum  usually  at  the  water  level.  A  separate  pipe,  3,  called  the 
down  -flow  pipe  is  attached  to  the  end  of  the  drum  at  its  lowest 
point,  the  other  end  being  connected  with  the  lower  end  of  all 
the  coils.  The  circulation,  due  to  the  varying  density  of  the 
water  is,  i,  from  the  drum,  2,  through  the  down  flow  pipe,  3,  to 
the  coils,  and  4,  back  to  the  drum  which  it  enters  as  a  mixture 
of  steam  and  water. 

The  upflow  coils  are  of  small  diameter  while  the  down  flow 
pipe  is  much  larger.  For  the  proper  flow  of  the  water,  the 
cross  sectional  area  of  the  down  flow  pipe  should  be  equal  to  the 
sum  of  all  the  cross  sectional  areas  of  the  coils,  as  must  be 
evident. 


Advantages  of  Water  Tube  Boilers. — With  the  water  tube 
boiler,  the  fact  that  the  full  force  of  the  steam  pressure  cannot 
bear  on  any  one  extended  surface  involves  that  in  the  event  of 


492  SELF-PROPELLED  VEHICLES. 

overheating  or  sinking  of  the  water  level,  only  one  or  two  of  the 
tubes  may  burst  with  no  very  serious  consequences. 

In  the  ideal  water  tube  boiler,  however,  the  tubes  would  run 
across  the  draught  through  a  portion  of  their  length,  at  least, 
thus  making  possible  a  greater  absorption  of  heat,  through  the 
breaking  of  the  air  currents.  This  result  is  immensely  increased 
when  the  successive  rows  of  tubes  are  staggered,  so  as  to  still 
further  divide  up  the  draught  currents. 


FIG.  353. — The  Ofeldt  water  tube  boiler  (automobile  type).  It  consists  of 
a  central  verticle  drum,  surrounded  by  a  number  of  pipe  coils  which 
are  connected  to  the  drum  at  its  extremities.  The  drum  holds  a  re- 
serve of  water,  which,  when  the  boiler  is  in  operation,  circulates 
through  the  coils  absorbing  heat  from  the  fire,  and  re-entering  the 
drum  at  the  top  as  water  and  steam.  The  amount  of  water  in  the 
drum  varies  from  three  gallons  in  the  smallest  size  to  eight  gallons 
in  the  24-inch  boiler.  Steam  is  taken  from  the  top  of  the  drum  and 
passed  through  a  superheater  before  delivery  to  engine. 

The  Ofeldt  Water  Tube  Boilers. — These  boilers  are  built  with 
both  horizontal  and  vertical  drums.  The  vertical  drum  type  is 
most  in  use  for  automobiles  while  those  with  horizontal  drums 
are  adapted  to  marine  use. 

As  shown  in  fig.  353,  the  first  mentioned  type  consists  of  a  central  drum 
made  of  standard  boiler  pipe,  the  same  height  as  the  boiler  and  five 
inches  or  more  in  diameter,  according  to  the  size  of  the  boiler.  It  has 
a  half  inch  bottom  securely  welded. 

The  stand  pipe  is  covered  with  a  steel  cap,  on  which  extend  three  arms 
to  the  boiler  cover,  holding  the  boiler  proper  in  the  casing.  The  cap  is 


BOILERS  AND   FLASH  GENERATORS. 


4.93 


threaded  and  securely  fitted  to  the  stand  pipe.  The  reserve  of  water  in 
the  stand  pipe  and  coils  varies  from  three  gallons  in  the  smallest  size  to 
eight  gallons  in  the  twenty-four  inch  size  boiler. 

The  coils  are  made  of  one-eighth  iron  pipe  in  the  small  sized  boiler, 
and  a  combination  of  one-eighth  and  one-quarter  pipe  in  the  larger  sizes. 
They  are  coiled  at  a  pitch  of  i  1-4  inches  to  give  the  proper  circulation 
and  prevent  the  pipes  from  being  clogged.  These  coils  are  attached  to  the 
stand  pipe  at  the  top  and  bottom  with  right  and  left  connections. 


FIG.  354. — The  Ofeldt  water  tube  boiler  (marine  type).  This  boiler  con- 
sists of  two  horizontal  drums  connected  on  each  side  by  numerous 
vertical  up  flow  coils.  Between  the  two  series  of  coils  are  a  set  of 
down  flow  coils  connected  to  the  two  drums.  The  cooler  water 
in  the  upper  drum  flows  down  through  these  coils  to  the  lower  drum, 
thence  up  through  the  up  flow  coils  absorbing  heat  from  the  fire  and 
re-entering  the  upper  drum  as  steam  and  water. 

The  standard  dimensions  of  the  vertical  drum  type  as  manu- 
factured are  as  follows: 


Size 

155/2  inches 
16 
18 
20 

22 

24    " 

28 

32  " 
36  " 


Height 
173/2  inches 


18 

20 
21 
21 
24 

30 
42 


Weight 
145  pounds 

145     " 

165    " 

210      " 
300      " 

345    " 

525    " 

1000      " 

1500  " 


H.  P. 

4  to    6 
4"     6 

6  "    8 

8  "  10 

10  "  12 

12  "  15 

20 
30 
40 


494 


SELF-PROPELLED    VEHICLES. 


These  boilers,  as  listed  according  to  the  builders,  are  rated 
when  used  in  connection  with  a  single  or  double,  double  acting 
high  pressure  engine,  operating  under  250  pounds  steam  pressure, 
turning  400  revolutions  per  minute  and  without  vacuum. 

When  used  in  connection  with  compound  engines  they  will  give  half  as 
much  again  as  the  listed  ratings,  and  for  marine  use  in  connection  with 
triple  expansion  engines  they  will  give  just  double  the  high  pressure 
rating.  Thus  the  2&-inch  boiler  24  inches  high  is  20  H.  P.  with  a  double 
acting,  high  pressure  engine;  with  a  compound,  30  H.  P.  and  with  a 
triple  expansion,  40  H.  P.  If  the  boilers  are  made  higher  than  listed — 
within  a  reasonable  limit — it  will  increase  the  H.  P.  from  one  to  three  for 
every  six  inches  added  to  height.  The  steaming  capacity  of  a  boiler  also 
depends  upon  the  fuel.  These  ratings  are  made  with  kerosene  as  fuel. 


FIG.  355. — The  "Walker  semi-flash  steam  generator.  It  consists  of  a  cen- 
tral vertical  drum  surrounded  by  pipe  coils.  The  feed  water  enters 
the  top  coil  and  flows  down  to  the  fifth  coil,  raising  its  temperature" 
to  near  the  boiling  point.  From  the  fifth  coil  it  flows  into  the  bot- 
tom of  the  central  drum,  thence  into  six  flash  steam  generating  coils 
and  back  to  the  steam  space  of  the  drum.  From  the  top  of  the 
drum  steam  is  drawn  off  and  carried  down  to  the  lowest  coil  and 
superheated  before  delivery  to  the  engine. 

Semi=flash  Boilers. — Boilers  of  this  type  are  a  combination  of 
the  shell  and  flash  boiler.  The  volume  of  water  carried  in  the 
shell  gives  considerable  reserve  power,  hence,  the  boiler  does  not 
become  inoperative  in  case  of  a  temporary  derangement  of  the 
feed  pump.  Two  examples  of  semi-flash  boilers  are  shown  in 
figs.  355  and  357. 


BOILERS  AND  FLASH  GENERATORS. 


495 


The  Walker  Semi=flash  Boiler. — This  boiler  is  provided  with 
a  non-tubular  shell  around  which  is  placed  a  number  of  coils  of 
pipe  as  shown  in  fig.  355.  The  five  coils  at  the  top  are  called  the 
water  pre-heating  coils. 

Cold  water  from  the  feed  pump  enters  the  topmost  coil  and  flows  down 
coil  by  coil,  until  it  reaches  the  fifth  coil. 

At  this  point  the  water  is  raised  almost  to  the  boiling  point.  These 
five  coils,  thus  form  a  feed  water  heater.  The  water  passes  from  the 
fifth  or  lowermost  of  the  pre-heating  coils  into  the  bottom  of  the  central 
drum. 


FIG.  356.— The  Geneva  Carriage  Boiler.  This  boiler  consists  of  several  coils 
of  tubing  connected  at  inner  and  outer  extremities  to  headers,  as  shown. 
The  water  and  steam  chamber  above  is  constructed  like  an  ordinary 
flue  boiler. 

From  this  central  drum,  the  water,  already  at  the  boiling  point,  is 
delivered  into  six  flash  steam  generating  coils.  These  six  coils  are  placed 
one  below  the  other,  directly  beneath  the  five  water  pre-heating  coils 
above  referred  to.  Each  of  these  flash  steam  generating  coils  is  inde- 
pendently, connected  to  the  central  stand-pipe.  In  shape,  these  coils  are 
volute.  The  outer  terminal  of  each  of  these  coils  is  connected  to  the 
bottom  of  the  central  drum  below  the  water  level,  while  the  inner  ter- 
minal is  carried  up  and  connected  to  the  drum  at  a  point  above  the  level 
to  which  the  water  in  the  central  drum  ever  rises.  By  this  plan,  the  hot 
water  which  the  pre-heating  coils  deliver  into  the  central  drum,  is  forced 
to  rapidly  circulate  through  these  coils  and  is  flashed  into  steam,  which 
is  collected  in  the  top  of  the  central  drum. 

From  the  top  of  the  central  drum,  the  steam  is  drawn  off  and  carried 
down  to  the  very  bottom  of  the  generator  and  passed  through  a  super- 
heating coil  located  directly  in  the  fire  where  the  steam  is  dried  and  super- 
heated, that  is,  raised  to  a  temperature  higher  than  that  corresponding 
to  its  pressure. 


496 


SELF-PROPELLED    VEHICLES. 


The  Lane  Semi=flash  Boiler. — This  boiler,  shown  in  fig.  357, 
consists  of  one  continuous  set  of  coils,  superposed  on  a  tubular 
shell.  Connection  between  the  coils  and  shell  includes  a  separator. 

The  feed  water,  which  enters  the  uppermost  coil,  is  first  heated  by  the 
spent  gases  that  are  too  cool  to  effectively  heat  the  hotter  parts  of  the 
boiler  below. 

The  water  passes  continuously  from  the  upper  coil  through  each  suc- 
ceeding one  below,  and  as  it  is  heated,  comes  into  contact  with  still  hotter 
surfaces  in  progressing  (as  in  a  flash  boiler)  till  it  issues  from  the  bottom 
coil  as  steam  and  water  into  the  centrifugal  separator  at  the  side. 


FIG.  357. — The  Lane  boiler.  The  feed  water  enters  at  the  top  of  the  coil 
and  passes  continuously  from  the  upper  coil  through  each  succeed- 
ing1 one  below,  coming1  in  contact  with  still  hotter  surfaces  as  it 
progresses  (as  in  a  flash  boiler)  till  it  issues  from  the  bottom  coil 
as  steam  and  water  into  the  centrifugal  separator  at  the  side.  From 
the  top  of  the  separator  the  steam  that  has  been  generated  in  the 
coil  passes  to  the  upper  part  of  the  shell  boiler,  located  beneath 
the  coil,  and  the  water  by  gravity  to  the  lower  part.  Steam  is 
drawn  from  the  top  head  of  the  shell  boiler. 

From  the  top  of  the  separator  the  steam  that  has  been  generated  in  the 
coil  passes  to  the  upper  part  of  the  shell  boiler,  located  beneath  the  coil, 
and  the  water  by  gravity  to  the  lower  part.  Steam  is  drawn  from  the 
top  head  of  the  shell  boiler. 

The  coils  being  somewhat  removed  from  the  most  intense  heat  are 
made  of  brass,  a  metal  that  conducts  the  heat  through  it  more  readily 
than  steel. 

The  shell  portion  is  of  pressed  steel  with  lower  head  and  side  walls  of 
one  piece  and  seamless.  The  tubes  are  one  inch  in  diameter  and  welded 
to  the  lower  head. 


BOILERS  AND  FLASH  GENERATORS. 


497 


Serpollet's  Flash  Boilers. — The  first  real  impulse  to  the 
modern  steam  carriage  was  the  invention  by  Leon  Serpollet  in 
1889  of  the  famous  "instantaneous  generator,"  known  by  his 
name.  It  consisted  of  a  coil  of  one  and  one-half  inch  lap-welded 
steel  tubing  flattened  until  the  bore  was  of  "almost  capillary 
width" — this  he  later  increased  to  about  one-eighth  inch — and 
this,  surrounded  by  a  cast-iron  covering  to  protect  the  steel  from 
corrosion  by  heat,  was  exposed  to  the  fire.  The  result  was  an 
extremely  rapid  generation  of  steam,  the  coil  being  first  heated, 
and  the  water  being  vaporized  almost  as  soon  as  it  was  injected 
:ito  the  tube. 


FIG.  358. 


FIG.  359. 


?IO.  358.  —Earliest  Form  of  the  Serpollot  Flash  Generator ;  a  coil  of  flattened  steel  tubing. 

FlO.  359.— Second  Form  of  the  Serpollet  Flash  Generator  :  a  series  of  tubes  pressed  as 
shown,  bent  U-shape  and  nested  ;  the  extremities  being  connected  by  joints  and  bent 
unions. 

Later,  he  improved  the  efficiency  of  his  coil  by  corrugating  its 
surface.  With  such  a  generator  of  108  square  inches  of  heating 
surface  more  than  one  boiler  horse  power  could  be  developed, 
the  average  hourly  evaporation  being  forty  pounds  of  water. 

The  usual  working  pressure  was  300  pounds  to  the  square  inch, 
but  each  tube  could  bear  a  test  as  high  as  1,500  pounds. 

One  great  advantage  lay  in  the  fact  that  the  high  velocity  required  by 
the  steam  and  water  in  the  narrow  tube  served  to  keep  the  surface 
thoroughly  free  from  sediment  and  incrustations.  For  vehicles  requiring 
an  additional  generative  power  two  such  coils  were  used,  one  above  the 
other,  the  water  being  injected  into  the  lower  and  the  upper  one  serving 
to  superheat  the  steam. 


498 


SELF-PROPELLED    VEHICLES. 


To  stop  the  engine  it  was  necessary  only  to  shut  off  the  water  feed 
pump,  with  the  result  of  stopping  the  generation  of  steam  at  once. 

In  improved  boilers  of  the  Serpollet  type  a  number  of  straight  tubes 
were  united  by  bent  joints  and  nested,  the  several  layers  being  connected 
in  series.  Moreover,  each  tube  length  was  flattened,  so  as  to  form  a 
U-shape,  or  crescent,  in  its  cross-section,  which  arrangement  greatly  in- 
creased its  evaporating  capacity.  But  the  most  efficient  form  was  reached 
in  the  design  shown  in  Fig.  361,  which  shows  three  superposed  sections 
of  tubing;  the  lowest,  four  tiers  of  coil;  the  second,  six  tiers  of  "zig- 
zag," the  successive  tiers<  being  staggered,  as  shown ;  the  third,  several 
tiers  of  flattened  tube  twisted  to  angles  of  about  forty-five  degrees. 


fia.  360,-LaterForinof  the  Serpollet  Flash  Generator,  consisting  of  three  layers  of 
tubing.  The  four  lowest  tiers  shown  form  a  coil  into  which  the  feed  water  is  injected; 
the  second  series  of  six  tiers  are  arranged  "  zig-zag,"  like  the  nested  tubes  shown 
in  Fig.  344  ;  the  third,  or  topmost,  series  of  four  tiers  are  also  arranged  "  zig-zag,  but 
are  flattened  and  then  twisted  as  shown. 

The  water  is  fed  to  the  lowest  section,  which  is  immediately  exposed 
to  the  fire,  being  thence  passed  to  the  second,  whose  available  heating 
surface  is  of  the  greatest  possible  dimensions,  and  finally  delivered,  as 
superheated  steam,  from  the  uppermost  twisted  coils.  The  several  sec- 
tions of  tubing  are  connected  together  in  series  by  bends  and  unions 
outside  the  case,  as  shown,  and  the  entire  generator  is  enclosed  in  a 
double  sheet-iron  casing  packed  with  asbestos.  By  the  arrangement  of 
the  tubing,  as  here  shown,  the  full  cower  of  the  heater,  in  both  draught 


BOILERS  AND  FLASH  GENERATORS. 


499 


and  radiated  heat,  is  utilized,  as  In  the  type  of  boiler  shown  in  Fig.  361, 
but  the  circulation  of  the  water  is  perfectly  under  control  and  rapid 
generation  of  steam  assured. 

For  a  six-horse  power  boiler  of  this  type  the  outside  dimensions,  includ- 
ing heater  space,  are  about  2l/2~x.il/y  feet,  the  total  tube  length,  ninety- 
five  feet,  and  the  heating  surface,  about  twenty-five  square  feet;  giving 
a  generator  of  convenient  size  for  a  four-seat  road  carriage. 


FIG.  361,-Recent  Form  of  the  Serpollet  Flash  Generator.  In  this  type  the  twisted  tubes 
are  placed  at  the  bottom  and  the  "  zig-zag  "  nested  tubes  at  the  top.  The  reason 
for  this  arrangement  is  that  twisting  the  tubes  affords  a  much  larger  heating  sur- 
face ;  hence  these  tubes  are  directly  exposed  to  the  fire. 

Of  Flash  Generators  fn  General. — Following-  along-  the  lines 
of  Serpollet's  famous  "flash"  generator,  with  its  numerous  ad- 
vantages in  point  of  quick  steam,  high  pressure  capacity,  free- 
dom from  scale  deposits,  and  complete  immunity  from  explo- 
sion, several  designers  of  steam  carriages  and  wagons  have  pro- 
duced improved  "boilers"  of  similar  description. 


500  SELF-PROPELLED    VEHICLES. 

Serpollet's  first  generator,  as  applied  to  his  light  steam  carriage  of 
1889,  was  merely  a  coil  of  flattened  tubing. 

Later  two  such  coils,  connected  in  series,  formed  his  generator,  and 
finally  the  complicated  trains  of  coils  and  bent  tubing. 

In  the  latest  generators  described  the  water  is  fed  to  the  lowest  tier 
of  tubing,  and  the  steam  is  taken  off  at  the  top,  as  in  the  several  types 
of  coiled  water  tube  boilers,  already  described. 

The  contrary  procedure  is  followed  in  most  of  the  really 
successful  flash  generators  produced  by  other  inventors.  The 
Blaxton  generator  feeds  from  the  lowest  water  coil,  but  the  Simp- 
son-Bodman,  White  Automobile  Manufacturing  Co.,  and  others 
feed  from  the  top  and  superheat  the  steam  in  the  lowest  coils. 

This  seems  to  be  the  more  logical  process  for  this  type  of  gen- 
erator, since,  as  the  water  is  explosively  vaporized  by  contact 
with  the  heated  tubes,  it  follows  that  the  progress  should  be 
from  the  lowest  to  the  highest  temperature,  vaporizing  and  super- 
heating the  steam,  rather  than  allowing  it  to  follow  a  course 
from  higher  to  lower  temperature,  with  the  accompanying  con- 
sequence of  loss  of  heat.  By  making  the  tubes  of  sufficient 
capacity  to  vaporize  a  good  quantity  of  water,  surprisingly  high 
temperatures  may  be  obtained  in  a  short  time. 

The  White  Flash  Generator. — This  flash  boiler,  or  generator 
as  it  is  called,  consists  of  nine  coils  of  steel  tubing  placed  one 
above  the  other  and  connected  in  series.  In  both  the  small  and 
large  generators  used  in  the  White  steam  cars  the  generator 
tubing  is  of  one-half  inch  internal  diameter,  but  the  length  of 
the  tubing  differs,  of  course,  for  the  two  sizes. 

Fig.  362  shows  diagrammatically  the  circulation  of  the  water 
and  steam  through  the  generator.  In  operation,  water  is  pumped 
into  the  upper  coil,  and  in  passing  through  each  coil,  it  must  rise 
to  an  elevation  higher  than  the  first  or  upper  coil. 

In  effect,  this  forms  a  series  of  traps,  and  as  is  shown  in  the 
diagram,  the  water  or  steam  in  order  to  pass  from  one  coil  to 
that  next  below,  must  be  forced  up  to  a  level  above  the  top  coil 
before  it  passes  down  to  the  next  lower  coil. 

This  trapping  of  the  water  gives  the  generator  a  certain  amount  of 
reserve  capacity  and  prevents  the  water  passing  directly  through  the 
generator  to  the  engine,  as  it  would  otherwise  be  likely  to  do  on  a  hard 


BOILERS  AND  FLASH  GENERATORS.  501 

pull,   and   hot   water   or   wet   steam   would   be   drawn   into   the   engine 
cylinders. 

It  also  prevents  the  steam  rising  to  the  top  and  the  water  settling  to 
the  bottom,  as  is  the  natural  tendency. 

There  is  but  a  very  small  quantity  of  water  and  steam  in  the 
generator  at  any  given  moment  (in  the  larger  car  the  total  capac- 
ity of  the  generator  is  less  than  one-third  of  a  cubic  foot),  but 
the  process  of  making  steam  is  so  rapid  with  the  flash  system  of 
generation,  that  the  rate  of  steam  production  follows  the  changes 
in  the  intensity  of  the  fire  without  any  appreciable  lapse  of  time. 


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FIG.  362. — Diagram  showing  circulation  through  the  White  flash  boiler. 
In  operation,  the  water  is  pumped  into  the  upper  coil,  through  the 
pipe  marked  "water  intake,"  passing  around  through  coil  No.  1,  then 
up  through  tubing  1A,  and  down  to  coil  2,  through  coil  2  up  to 
tubing  2  A  and  down  to  coil  3,  through  which  it  passes  up  through 
tubing  3  A  and  back  down  to  and  through  coil  4,  up  through  tubing 
4  A  and  down  through  coil  5,  up  through  5  A  down  through  coil 
6,  up  through  6  A  and  down  and  through  coil  7,  up  through  7  A, 
down  and  through  coil  8,  up  through  8  A  and  down  into  and  through 
coil  9,  the  last  and  lowermost  coil  of  tubing,  being  directly  over 
the  fire  where  the  steam  is  highly  superheated,  passing  out  of  the 
generator  from  this  point  to  the  engine.  The  water  or  steam,  in 
o-pder  to  pass  from  one  coil  to  that  next  below,  must  be  forced  up 
to  a  level  above  the  top  coil,  and  must  then  pass  down  again.  This 
feature  prevents  water  from  descending  by  gravity,  and  renders 
the  circulation  down  through  the  generator  dependent  upon  the 
action  of  the  pumps,  or  in  other  words  a  forced  circulation. 


502  SELF-PROPELLED    VEHICLES. 

Seamless  Steel  Tubing  for  Flash  Boilers. — Improved 
methods  in  the  manufacture  of  steel  tubing  have  resulted  in  an 
article  almost  indestructible  and  has  made  possible  the  develop- 
ment and  successful  application  of  the  flash  system  of  steam 
generation  for  automobile  propulsion. 

Prof.  Carpenter  of  Cornell  University  has  subjected  samples  of 
tubing  used  in  flash  boilers,  to  a  pressure  of  18,900  pounds  per 
square  inch  without  showing  any  signs  of  rupture.  Owing  to  the 
limitations  of  the  testing  apparatus  on  hand,  he  was  unfortunately 
unable  to  ascertain  the  bursting  strength. 

Seamless  steel  tubing  is  now  manufactured  on  an  extensive  scale,  to 
meet  the  demands  of  flash  boiler  manufacturers  and  for  other  purposes 
where  an  article  possessing  great  strength  is  required. 


CHAPTER  THIRTY-SEVEN. 

LIQUID    FUEL    BURNERS    AND    REGULATORS. 


Of  Liquid  Fuels  in  General. — All  light  steam  carriages,  and 
many  heavier  vehicles  as  well,  use  liquid  fuel,  oil  or  mineral  spirit, 
to  produce  heat  for  their  boilers.  Such  liquid  fuel  is  not  burned 
in  liquid  form,  as  is  oil  in  an  ordinary  lamp,  but  is  vaporized  by 
heat,  the  vapor  or  gas  thus  produced  being  fed  to  the  burner  and 
ignited,  in  the  same  manner  as  ordinary  coal  gas  used  for  light 
or  heat  in  houses.  It  would  be  impracticable  to  carry  gas  in  tanks 
on  steam  carriages,  since  the  difficulty  of  storing  and  replenishing 
the  supply  would  be  greatly  increased.  By  the  use  of  liquid  fuels 
a  vast  saving  is  made  possible,  both  in  space  and  weight,  while 
their  consumption  in  gaseous  form  is  another  element  of  economy. 

Advantages  in  Using  Volatile  Fuels. — A  prominent  English 
authority  on  motor  carriages  gives  the  following  five  considera- 
tions of  advantage  in  the  use  of  liquid  fuels : 

1.  Their  combustion  is  complete,  no  heat  being  lost  in  the  form 
of  smoke  or  soot. 

2.  They  produce  no  ashes  or  clinkers,  which  must  be  periodi- 
cally cleaned  out.    Hence  there  is  no  loss  of  heat  or  drop  in  steam 
pressure,  due  either  to  this  cause  or  to  the  renewal  of  coal. 

3.  The  flues  are  never  incrusted  with  soot,  which  involves  thr 
best  conditions  for  use  of  heat. 

4.  The  temperature  of  the  escaping  gases  is  lower  than  with 
a  coal  fire,  since  there  is  no  need  that  the  air  required  for  com- 
bustion should  force  its  way  through  a  thick  layer  of  burning 
fuel.     Whence  the  uptake  temperature  is  generally  about  400°, 
Fahrenheit,  instead  of  between  600°  and  700°,  as  with  the  use  of 
coal  fire. 

5.  Since  the  fuel  is  burned  in  fine  particles,  in  close  contact 
with  the  oxygen  of  the  air,  only  a  small  excess  of  air  over  that 
actually  required  for  combustion  is  admitted  to  the  burner.    The 
opposite  is  the  case  with  coal. 

503 


504. 


SELF-PROPELLED    VEHICLES. 


As  may  be  readily  surmised,  the  calorific  value  of  liquid  fuels 
is  far  greater  than  that  of  coal.  It  has  been  estimated  that,  taking 
the  two  weight  for  weight,  petroleum  oil  has  about  twice  the 
heat  efficiency  of  coal.  Since,  therefore,  equal  weights  of  both  vari- 
eties of  fuel  occupy  about  equal  spaces,  it  follows  naturally  that 
petroleum  products  are  far  more  economical  and  serviceable  for 
use  in  vehicles  of  any  description,  or  in  boats  and  ships,  where 
the  considerations  of  weight  and  space  occupied,  in  ratio  to  the 
power,  are  all-important. 

The  liquid  fuels  most  commonly  used  are  kerosene  and  gaso- 
line, both  being  vaporized  by  the  heat  of  the  burner. 


FIG.  363<— Plan  and  Part  Section  of  a  Typical  Gasoline  Burner  foi    Steam 
Carriage  Use. 

The  Gasoline  Burner. — Very  nearly  the  typical  gasoline  burner 
for  steam  carriages  is  shown  in  an  accompanying  figure.  It  con- 
sists of  a  flattened  cylindrical  chamber,  pierced  from  head  to  head 
by  a  number  of  short  tubes,  each  of  which  is  expanded  into  the 
holes  prepared  for  it  and  flanged  over  to  make  a  secure  joint, 


BURNERS  AND  REGULATORS,  505 

somewhat  after  the  manner  of  a  well-made  boiler  flue  attachment. 
These  air  tubes,  as  they  are  called,  are  open  to  the  air  at  top  and 
bottom,  having  no  communication  with  the  interior  of  the  cylin- 
drical chamber  above  referred  to.  The  gasoline  enters  the  cham- 
ber, from  a  nozzle  at  the  end  of  the  feed  pipe  and  through  a  tube 
ertering  at  one  side  of  the  cylinder  and  extending  inward  about 
two-thirds  of  the  diameter.  This  tube  is  called  the  "mixing  tube," 
and  its  function  is  to  make  a  mixture  of  air  and  gasoline  vapor 
that  will  burn  readily  in  the  atmosphere.  Having  entered  the 
cylindrical  chamber,  there  is  no  avenue  of  escape  for  the  in- 
flammable gas  except  through  the  circular  series  of  pin-holes, 
which  surround  each  one  of  the  air  tubes,  as  may  be  seen  on  the 
cut  of  the  top  of  this  burner.  It  is  at  these  minute  perforations 
that  the  gasoline  gas  is  ignited,  the  combustion  being  rendered 
perfect  by  the  air  admitted  through  the  air  holes  previously  men- 
tioned. 

The  Storing  and  Feeding  of  Gasoline. — The  liquid  gasoline 
for  supplying  gas  to  the  burner  of  a  steam  carriage  is  carried 
in  a  tank,  disposed  generally  to  the  rear  of  the  body,  and  suffi- 
ciently separated  from  the  burner  to  avoid  all  dangers  that  might 
arise  from  leaks  or  overheating.  Within  this  storage  tank  a  good 
pressure  of  air  is  maintained — generally  between  50  and  100 
pounds  to  the  square  inch — from  a  separate  air  tank,  supplied  by 
a  pump.  This  pressure  is  sufficient  to  force  the  liquid  gasoline 
into  the  vaporizing  tubes,  when  the  supply  cock  is  opened.  After 
it  has  been  vaporized  the  circulation  continues,  as  controlled  by 
the  steam  pressure  diaphragm  regulator,  which  operates  a  needle 
valve  on  the  tube  supplying  the  burner,  the  amount  of  gas  and 
liquid  gasoline  moving  between  the  supply  tank  and  the  burner 
being  thus  determined.  If  the  fire  is  blown  out  in  the  draughts 
created  by  travel,  the  difficulty  may  be  generally  remedied  by  using 
higher  air  pressures  in  the  tank.  Some  drivers  have  used  as  high 
as  100  pounds  and  over. 

The  Automatic  Fuel  =  Feed  Regulator. — The  fuel-feed  regu- 
lator, of  which  there  are  several  serviceable  forms,  is  one  of  the 
most  necessary  attachments  of  a  steam  carriage.  Generally,  it 
consists  of  a  diaphragm,  which,  actuated  by  steam  pressure  from 
the  boiler,  automatically  closes,  or  partly  closes,  a  needle  valve, 
thus  regulating  the  amount  of  fuel  fed  to  the  burner.  Several  such 


506  SELF-PROPELLED    VEHICLES. 

apparatus  are  shown  in  section  in  Figs.  365-366.  There,  as 
may  be  seen,  the  diaphragm  is  fixed  across  the  tube  leading  from 
the  steam  space  of  the  boiler. 

Against  its  inner  side  bears  a  solid  head,  or  pressure  cap,  carry- 
ing a  rod,  at  the  farther  end  of  which  is  a  needle  valve.     The 


FIG.  364. — The  Lane  burner.  This  is  made  entirely  of  tubing.  The  mix- 
ing tube  exceeds  in  length  the  diameter  of  the  burner,  thus  in- 
suring a  uniform  mixture  of  air  and  vapor.  The  flames  are  ar- 
ranged in  straight  rows  separated  by  narrow  air  passages,  thus 
supplying  oxygen  for  combustion  to  each  side  of  each  flame.  The 
cut  also  shows  the  vaporizing  tubes  within  the  burner  casing  and 
the  igniting  torch  below  them.  The  latter  is  a  perforated  tube  en- 
closed in  an  absorbent  envelope.  The  tube  is  connected  with  a  cup 
located  outside  the  burner.  One  valve  only  is  operated  to  start  this 
burner.  There  is,  however,  a  second  valve  in  fuel  feed  pipe,  ac- 
cessible from  driver's  seat,  and  also  a  valve  for  controlling  pilot 
light,  but  these  are  seldom  used. 

*» 

pressure  cap  is  normally  held  against  the  diaphragm  by  a  strong 
spring.  When  sufficient  steam  pressure  bears  upon  the  dia- 
phragm, the  spring  is  compressed,  allowing  the  rod  attached  to 
the  head  to  be  pushed  inward,  thus  regulating  the  needle  valve, 
according  to  requirement. 

The  instrument,  thus  formed,  consists  of  two  parts.  The  one 
is  the  pressure  chamber  containing  the  spring,  whose  pressure 
on  the  head  is  regulated  by  an  adjusting  screw,  through  the  shaft 


'BURNERS  AND  REGULATORS. 


507 


of  which  passes  the  valve  rod.  The  other  is  the  gasoline  cham- 
ber, into  which  the  fuel  for  the  burner  is  admitted  to  the  left 
of  the  point  of  the  needle  valve;  its  outlet  being  controlled,  as 
shown,  by  two  hand-wheel  valves — one  leading  to  the  main 
burner  through  the  mixing  tube,  the  other  being  intended  to  let 
out  a  sufficient  supply  of  gasoline  to  the  starting  device,  which 
may  be  a  detachable  "torch,"  or  auxiliary  vaporizer,  or  some 
arrangement  of  drip  cup  and  preliminary  generating  coil.  This 
arrangement  of  the  valves  is  shown  in  different  cuts  of  burners 
and  automatic  regulators,  being  there  sufficiently  designated. 
Thus,  as  shown  in  the  figures,  the  valve  rod,  in  entering  the  gaso- 
line end  of  the  regulator,  passes  through  a  stuffing  box,  so  as  to 
prevent  all  leakage  at  that  end. 


FIG.  365.— Fuel  Feed  Regulator  of  a  Steam  Carriage  Burner,  Intended  for 
Use  with  "Torch"  Burner  Kindler  or  Auxiliary  Vaporizer.  A  is  the  hand 
wheel  and  needle  valve  regulating  the  feed  to  the  main  burner;  B,  the 
hand  wheel  and  valve  for  operating  the  torch;  C,  the  spring  and  header 
attached  to  the  main  valve  rod;  D,  the  diaphragm  against  which  steam 
bears,  regulating  the  main  valve  according  to  pressure.  The  liquid 
gasoline  is  admitted  at  a  port  on  the  left-hand  extremity  of  the  regu- 
lator tube,  near  the  end  of  the  needle  valve  on  the  main  rod. 

Of  course,  until  there  is  sufficient  heat  generated  to  vaporize 
gasoline  for  the  regular  burner  and  generate  steam  pressure  in 
the  boiler,  the  automatic  regulator  cannot  operate,  as  described, 
and  the  flow  of  gasoline  to  the  starting  burner  or  vaporizer  is 
regulated  solely  by  the  hand  valves. 

Another  form  of  regulator,  shown  in  an  accompanying  cut, 
used  on  steam  wagons,  has  the  advantage  of  simplicity  in  this 
particular,  doing  away  with  both  spring  and  stuffing  box.  The 


508 


SELF-PROPELLED   VEHICLES. 


diaphragm  has  concentric  corrugations,  and  to  its  centre  is  at- 
tached a  valve  rod  having  longitudinal  groovings  to  permit  the 
fuel  to  enter  the  feed  tube  in  such  quantities  as  the  pressure  on 
the  other  face  of  the  diaphragm  will  permit.  Steam  pressure, 
being  thus  brought  to  bear,  tends  to  deform  the  diaphragm ;  hence 
compressing  the  valve  rod  and  decreasing  the  rate  and  quantity  of 
fuel  feed.  The  fuel  is  supplied  from  the  storage  tank  through  the 
port  into  the  lower  chamber  of  the  two  formed  by  the  diaphragm, 
as  may  be  readily  understood. 


FIG.  366. -Gasoline  Burner  Regulator,  operating  with  a  corrugated  dia- 
phragm, like  a  steam  gauge.  A  is  the  inlet  for  steam;  B,  the  inlet  for 
liquid  gasoline;  C,  the  port  leading  to  the  burner;  D,  the  diaphragm;  E, 
the  head  on  the  grooved  rod  of  the  valve;  F,  the  steam  chamber;  G,  the 
gasoline  chamber. 

Constructional  Points  on  Gasoline  Burners. — Several  steam 
carriage  burners  are  formed  by  riveting  together  a  steel  flattened 
cylindrical  pressing  and  a  plane  disc,  as  shown  in  a  former  figure, 
inserting  and  expanding  the  draught  tubes  into  suitably  arranged 
perforations,  as  is  done  with  the  flues  of  boilers.  Such  a  con- 
struction is  apt  to  be  faulty,  however,  owing  to  the  fact  that  the 
steel  plates  tend  to  warp  under  the  influence  of  heat,  causing  the 
draught  tubes  to  leak,  and  the  attachments  to  wear.  The  danger 
of  these  accidents  has  moved  several  inventors  and  manufacturers 
to  design  and  produce  burners  formed  with  a  cast  top  and  steel 
plate  base,  or  to  cast  both  elements.  By  the  use  of  castings  warp- 
ing is  positively  prevented,  and  leaking  at  the  joints  of  the  draught 
tubes  is  obviated. 

One  of  the  best-known  burners  of  this  construction  is  that 
widely  known  as  the  "Dayton,"  which  possesses  the  additional 
feature  of  supplying  gas  for  the  burner  flame  through  annular 
openings  around  each  of  the  draught  tubes,  instead  of  using  the 


BURNERS  AND  REGULATORS. 


509 


"pin-hole"  design,  already  described.  It  is  possible  to  construct 
with  this  feature,  since  the  air  tubes  are  cast  in  one  piece  with 
the  head  and  base  plates,  being  afterward  reamed  out,  so  as  to 
make  them  uniform  in  size.  In  addition  to  this  air  opening,  a 
counter-bore  is  sunk  in  the  top  plate  of  the  burner,  and  a  steel 
washer  is  fitted  into  it,  leaving  an  annular  opening  for  the  passage 
of  gas  in  the  inside  of  the  washer.  The  outside  of  the  washer 
has  a  number  of  small  openings  in  it,  so  that  each  air  tube  is  sur- 
rounded by  two  concentric  circles  of  flame.  This  construction 
affords  a  very  large  heating  capacity,  and  also,  as  is  claimed, 
prevents  the  top  of  the  burner  from  cracking,  also  less  liability 


FIG.  367.-The  Dayton   Burner,   showing  the   Starter  Box  and  Regulator  in 
Position. 

of  chocking  with  rust,  dust  or  carbonized  particles,  which  is  a 
frequent  source  of  annoyance  with  "pin-hole"  burners. 

An  Auxiliary  Coil  Starting  Device. — The  starter  used  with 
the  "Dayton"  burner,  already  described,  is  shown  on  page  509, 
Fig.  367.  There,  as  may  be  seen,  a  small  box,  called  a  "starter 
box,"  is  attached  at  one  side  of  the  burner  It  contains  a  short 
coil  of  tubing,  into  which  liquid  gasoline  may  be  admitted  by 
opening  the  valve  which  is  shown  at  the  side.  A  few  drops  of 
liquid  gasoline  are  then  allowed  to  drip  into  the  "starting  cup," 
beneath  the  coil,  and  this,  set  on  fire,  will  speedily  generate  suffi- 
cient gas  to  light  the  pilot  burner,  from  wh;ch,  in  turn,  the  main 


510 


SELF -PRO  FELLED  VEHICLES. 


FIG.  368. — The  Forg  generator  and  burner.  The  gasoline  supply  Is  car- 
ried through  a  pipe  entering  on  the  left  hand  ;side  and  passing  over 
the  burner  in  a  loop  form,  out  on  the  right  hand  side,  where  it 
passes  into  the  generator  box.  The  generator  box  is  made  of  sheet 
steel  suitably  perforated  and  so  arranged  that  while  the  fire  will 
burn  freely  inside  of  the  box,  it  will  not  blaze  up  on  the  outside. 


FIG.  369. — Stanley  burner,  showing  vaporizer  and  mixing1  tubes.  The 
bnrner  is  entirely  encased,  there  being  no  air  inlet  except  at  the 
mixing  tubes,  consequently  it  is  not  affected  by  air  currents.  The 
pilot  light  is  not  shut  off  by  the  automatic,  but  burns  continuously 
until  shut  off  by  hand  and  Is  just  strong  enough  to  hold  the  steam 
pressure. 


BURNERS  AND  REGULATORS. 


511 


burner  may  be  kindled  as  soon  as  the  vaporizing  tubes  are  suffi- 
ciently heated. 

As  soon  as  this  point  is  reached  the  needle  valve  to  the  main  burner, 
shown  at  the  right  hand  of  the  starter  box,  is  opened,  admitting  gas 
through  the  nozzle  into  the  mixing  tube. 

By  closing  this  valve,  the  main  fire  may  be  shut  off,  as  desired,  although 
the  pilot  light  continues  burning,  until  extinguished  by  shutting  off  its 
supply  of  gas,  which  is  never  modified  in  any  way,  being  out  of  reach 
of  the  automatic  regulator  controlling  the  fuel  feed  to  the  main  burner. 


AC 


FIG.  370. — The  White  flash  steam  generator  and  burner.  Fuel  passes 
through  Dice  A.  then  through  strainer  B.  From  the  strainer  it 
passes  through  pipe  H,  valve  J,  pipe  K,  valve  L,  pipes  M  and  HA  to 
vaporizer  N.  Gas  is  discharged  from  the  vaporizer  through  pipe 
NA  and  nozzle  O  into  burner  induction  tube  R.  Warming  up  valve 
G  is  supplied  through  pipe  I. 

The  White  Burner  and  Connections. — As  shown  in  fig.  370, 
the  burner  is  of  the  Bunsen  type,  the  gasoline  vapor  drawing 
back  through  the  mixing  tube  R,  sufficient  air  for  good  combus- 
tion. 

Fuels  of  the  lower  specific  gravities,  such  as  65  to  70  (Baume  Scale) 
require  more  air  than  those  of  higher  specific  gravities,  such  as  70  to  76. 
The  air  supply  may  be  regulated  by  the  air  shutter  S  on  the  mixing  tube. 
Usually  too  much  air  causes  the  fire  to  burn  very  blue  and  to  raise  off 
the  burner;  too  little  air  causes  the  fire  to  burn  with  a  red  and  yellow 


512  SELF-PROPELLED    VEHICLES. 

flame.  The  proper  flame  is  blue,  a  medium  between  the  light  and  heavy 
flame  just  described.  If  the  air  supply  be  not  correctly  adjusted,  it  causes 
the  burner  to  light  back  to  the  nozzle  and  is  sometimes  accompanied  by 
"howling." 

In  lighting  the  sub-burner,  the  valves  D  and  F  should  be  closed 
and  main  fuel  valve  opened  which  allows  fuel  to  come  through 
pipe  A  to  the  sub-burner  V.  Valve  F  should  now  be  opened 
one  turn,  door  W  opened  and  a  lighted  match  applied  inside. 
After  doing  this,  the  supply  valve  D  should  be  opened  slightly, 
closing  it  again  at  once,  leaving  it  open  about  one  second.  This 
operation  is  repeated  until  sufficient  gasoline  runs  into  the  drip 
cup  to  be  ignited  by  the  match.  Sufficient  fuel  should  be  kept 
in  the  drip  cup  by  opening  and  closing  D  to  warm  up  the  sub- 
burner.  When  the  sub-burner  becomes  hot  enough  to  vaporize 
the  gasoline,  fuel  will  cease  to  run  in  the  drip  cup  as  it  has  now 
become  a  gas  and  will  pass  up  through  the  pilot  light  grate 
and  burn  in  the  main  fire  box.  Valve  D  should  then  be  opened 
at  least  one  turn  and  left  open.  As  soon  as  the  gasoline  in  the 
drip  cup  is  all  burnt  out,  this  flame  should  burn  blue  and  soon 
heat  the  grate  red  hot.  This  can  be  seen  by  looking  through  the 
hole  in  the  boiler  casing.  As  soon  as  the  sub-burner  gets  warmed 
up,  the  flame  should  be  adjusted  by  valve  F. 

This  valve  regulates  the  strength  of  the  flame  and  should  be  turned 
up  or  down  until  a  steady  blue  flame  is  obtained  that  does  not  roar. 
In  case  the  sub-burner  goes  out,  but  is  still  hot  enough  to  vaporize 
the  fuel,  it  can  be  relighted  by  putting  a  match  through  the  hole  in  the 
casing  without  using  the  drip  cup. 

When  the  sub-burner  is  to  be  shut  off,  valve  D  is  closed  and  valve  F 
opened  wide.  This  frees  the  passages  in  the  sub-burner  of  gas  and  helps 
to  keep  them  clear  and  open.  Should  the  flame  in  the  sub-burner  be 
not  sufficiently  strong  with  valve  F  opened  two  turns,  there  is  probably 
some  obstruction  in  the  valve  and  it  should  be  examined  and  cleaned. 


CHAPTER  THIRTY-EIGHT. 

BOILER  ATTACHMENTS  AND  AUTOMATIC  REGULATING  DEVICES. 

Of  Boiler  Feeders  in  General. — There  are  two  different  kinds 
of  device  for  feeding  water  to  steam  boilers :  plunger  pumps 
operated  by  the  engine  or  by  a  separate  cylinder;  and  injectors, 
which  raise  and  feed  the  water  by  a  steam  jet  from  the  boiler  it- 
self. Injectors  are  largely  used  for  locomotives,  marine  and  sta- 
tionary boilers,  but  to  the  present  time  almost  not  at  all  in  steam 
road  carriages.  The  principal  reason  for  this  is  that  the  valves 
and  apertures  in  an  injector,  suited  for  a  light  carriage  boiler, 
would  have  to  be  made  so  small  that  they  would  be  constantly 
clogged  with  dirt  and  sediment,  hence  rendering  the  instrument 
inoperative.  Furthermore,  when  in  operation,  an  injector  would 
be  liable  to  fill  the  boiler  too  rapidly,  while  the  pressure  remained 
sufficient  to  raise  the  water,  thus  causing  priming;  and,  if  shut 
off  until  the  water  level  had  fallen  considerably,  would  cause 
damage  tc  the  boiler  by  flooding  it,  while  in  an  overheated  con- 
dition. 

Plunger  Pumps  and  By  =  Pass  Valves. — The  plunger  pumps 
used  to  feed  steam  carriage  boilers  are  most  often  operated  from 
the  cross-head  of  the  engine.  Consequently,  so  long  as  the  en- 
gine is  in  motion,  water  is  steadily  pumpea  into  the  boiler.  When, 
as  shown  by  the  water-glass,  the  level  is  too  high,  the  by-pass 
valve  may  be  opened,  and  the  water  pumped  from  and  back  again 
to  the  tank.  In  some  carriages  the  by-pass  is  always  operated  by 
hand;  in  others  it  is  also  controlled  by  some  kind  of  automatic 
arrangement.  The  automatic  control  of  the  by-pass  is  extremely 
desirable,  particularly  since  unskilled  engineers  most  often  have 
charge  of  carriages  and  are  exceedingly  liable  to  forget  the  small 
details  of  management.  On  the  other  hand,  many  automatic  de- 
vices get  out  of  order  altogether  too  easily,  and  leave  the  carriage 
driver  to  exercise  his  skill  and  judgment  at  an  unexpected  mo- 
ment. 

513 


514 


SELV -PROPELLED  VEHICLES. 


In  addition  to  the  danger  of  flooding  the  boiler,  the  opposite 
embarrassment  often  occurs — owing  to  some  disarrangement  the 
pump  may  fail  to  feed  enough  water  to  the  boiler,  or  may  not 
operate  at  all.  Then  it  is  necessary  to  use  a  supplementary  feeder, 
generally  a  hand  pump,  or  a  steam  pump  operated  by  a  separate 
cylinder.  Such  supplementary  steam  pumps  and  injectors  are 
commonly  arranged  to  start  automatically,  as  required,  but  may 
also  be  started  by  a  hand-controlled  valve.  Another  advantage 
involved  in  the  use  of  automatically  controlled  steam  pumps  is 
that  water  may  be  fed,  as  required,  to  the  boiler,  after  the  engine 


FIG.  371.— Section  of  a  Type  of  Plunger  Feed  Pump.  As  is  obvious,  the  valve 
opened  by  suction  of  the  up-stroke  Is  closed  by  compression  of  the  down- 
stroke,  and  vice  .versa.  This  pump  Is  equipped  with  a  double,  or  com- 
pound, valve,  which,  as  may  be  seen,  secures  perfect  balance  in  operation 
with  the  simplest  possible  constructions.  The  stem  of  the  suction  valve 
enters  a  bore  in  the  stem  of  the  outlet  valve.  Referring  to  the  lettered 
parts:  A  is  the  pivoted  lever  working  the  pump  from  the  crosshead  of 
the  engine;  B,  the  fulcrum  point;  C,  the  attachment  of  the  piston  rod, 
D;  E,  the  trunk  plunger;  F,  the  packing  cap;  G,  the  pump  cylinder;  H, 
nut  on  the  valve  chamber  port;  J,  the  valve  chamber;  K,  water  outlet 
valve;  L,  water  inlet  valve. 

has  ceased  motion,  and  it  is  desirable  to  leave  the  carriage  stand- 
ing with  steam  up.  In  this  condition,  however,  a  very  small 
amount  of  water  is  needed,  except  under  unusual  conditions. 

Operating  the  By -Pass  Valve. — The  driver  of  a  steam  car- 
riage must  constantly  watch  the  water-glass  in  order  to  inform 
himself  as  to  the  water  level  in  the  boiler.  On  noticing  that  the 
level  is  too  high,  or  is  rising  too  rapidly — the  proper  level  is 
generally  about  two-thirds  up  the  glass — he  opens  the  by-pass 


BOILER  ATTACHMENTS  AND  AUTOMATICS.  515 

valve  by  turning  a  small  wheel  placed  near  the  throttle  lever  be- 
side his  seat.  This  act,  as  already  suggested,  turns  the  water 
forced  by  the  pump  back  again  into  the  feed  tank,  a  three-way 
cock  controlling  its  travel. 

If,  after  the  water  has  been  led  from  the  boiler  for  some  time, 
the  level  begins  to  sink,  it  is  necessary  only  to  close  the  by-pass 
valve,  thus  resuming  the  feed.  If,  from  any  cause,  the  pump 
seems  unable  to  keep  up  the  water  level  in  the  boiler,  and  the 
reading  of  the  water-glass  is  verified  by  the  try-cocks,  thus  show- 
ing that  it  is  working  perfectly  and  is  unclogged  with  sediment, 
a  few  strokes  of  the  auxiliary  hand  pump  will  suffice,  if  no  auto- 
matic steam  pump  be  attached  to  the  carriage. 


FIG.  372. — A  hand  feed  -water  pump  for  use  on  cars  having  tubular 
boilers  working  on  moderately  high  steam  pressures.  The  handle 
is  arranged  to  fold  down  when  not  in  use. 


FIG.  373. — Hand  water  pumps  for  use  with  flash  boilers.  It  is  intended 
to  be  placed  in  front  of  seat,  between  the  two  passengers.  The 
bracket  in  center  being  movable,  enables  the  pump  to  be  placed  at 
any  height  to  suit  the  car.  The  water  connections  are  for  one- 
quarter  inch  pioe.  The  plunger  is  qu*te  small  as  the  resistance  to 
be  overcome — that  due  to  the  high  working  pressure  of  the  flash 
boiler — is  considerable,  in  fact  it  would  be  too  great  for  hand  opera- 
tion if  the  plunger  were  large  as  shown  in  fig.  372. 

Troubles  With  the  Pump. — Since  the  small  water  pumps  at- 
tached to  steam  carriages  are  of  the  simple  plunger  type,  failure 
to  supply  sufficient  water  to  the  boiler  may  generally  be  attributed 
to  loosened  packings  or  to  clogged  check  valves.  The  rapid  sink- 
ing of  the  level  in  the  water-glass  will  indicate  trouble  with  the 
pump,  except  when  ascending  a  high  hill.  In  the  latter  case  the 
fall  of  level  may  reasonably  be  attributed  to  the  unusual  steam 


516 


SELF-PROPELLED    VEHICLES. 


consumption.  Under  usual  circumstances,  the  trouble  is  due  to 
loosened  packings,  and  this  trouble  may  be  remedied  by  inserting 
new  packings,  although  particular  care  should  be  exercised,  so  as 
not  to  pack  the  plunger  too  tightly  and  cause  breakage. 

Boiler  Attachments :  Try-Cocks  and  Water  Glass — In  op- 
erating a  boiler  of  any  design  it  is  essential  both  for  safety  and 
efficiency  that  the  engineer  should  be  kept  constantly  informed 
on  the  level  of  the  water  and  the  pressure  of  the  steam.  For 
this  reason  boilers  are  fitted  with  try-cocks,  water  glass  and 


FIG.  374. — The  Ofeldt  automatic  water  regulator.  This  device  consists  of  a  column,  having 
an  expansion  tube  attached  at  right  angles.  A  lever,  with  the  fulcrum  braced  from 
the  top  of  the  water  column,  is  attached  by  a  joint  to  the  end  of  the  expansion  tube, 
with  the  lever  free  to  operate  the  by-pass  valve.  In  operation,  the  closing  and  opening 
of  the  by-pass  valve  depend  upon  the  expansion  and  contraction  of  the  brass  tube, 
•when  subjected  to  water_at  the  boiling  point  and  steam,  which  is  over  150  degrees 
hotter.  The  water  rises  in  the  boiler,  at  the  same  time  rising  in  the  regulator  watei 
column,  until  it  enters  the  expansion  tube,  causing  the  tube  to  contract  and  pulling 
on  the  lever,  thus  lifting  the  free  end  and  opening  the  by-pass  valve.  When  the  wntri 
has  been  evaporated  from  the  expansion  tube,  i  ormitting  the  steam  to  enter,  it  ex- 
pands and  presses  the  lever  out,  thus  closing  and  holding  the  by-pass  valve  shut. 
In  actual  operation  the  expansion  tube  finds  thr  exact  position  to  keep  the  water  in 
the  boiler  always  at  the  same  level.  Should  the  valve  by-pass  too  much  water,  01 
not  enough,  it  can  be  adjusted  to  shut  off  closer  or  open  wider  by  raising  or  lowering 
the  valve. 

steam  gauge,  all  of  which  are  depicted  in  accompanying  figures. 
There  are  usually  three  try-cocks,  as  shown,  the  upper  one  in- 
tended for  steam,  the  second  at  the  working  level  of  the  water, 
and  the  third  at  a  fixed  point  above  the  fire  line.  In  conditions 
of  uncertainty  in  the  action  of  the  water  glass  the  engineer  may 
find  out  whether  the  water  level  is  too  low  by  opening  the  lower 


BOILER  ATTACHMENTS  AND  AUTOMATICS.  517 

cock,  or  may  find  if  it  is  too  high  by  opening  the  two  upper  ones. 
In  making  test  it  is  necessary  to  leave  the  cock  open  sufficiently 
long  to  discover  whether  all  steam,  all  water,  or  a  mixture  of  both 
is  escaping. 

The  water  glass,  or  water  column,  furnishes  a  ready  means  for 
determining  the  exact  height  of  the  water  in  the  boiler. 


FIG.  375. — The  Ofeldt  automatic  fuel  regulator.  This  consists  of  two  concave  brass  discs 
with  a  steel  diaphragm  between  them,  held  together  with  screws,  leaving  a  small  space 
on  the  under  side  of  the  diaphragm  for  steam  and  a  space  for  fuel  on  the  upper  side. 
The  valve  consists  of  a  brass  seat  in  the  center  of  the  diaphragm,  with  a  specially  made 
hollow  fitting  which  the  valve  rests  against.  This  hollow  tube  is  the  end  of  the  supply 
pipe  to  the  burner  and  can  be  adjusted  to  shut  off  the  fire  at  any  desired  steam  pressure 
by  breaking  the  union  on  the  upper  side  of  the  regulator.  In  operation,  when  the  steam 
pressure  on  the  lower  part  of  the  diaphragm  has  reached  a  point  where  it  is  desired  to 
shut  off  the  fire,  the  diaphragm'is  pushed  upward,  pressing  the  metal  seat  upward 
until  it  closes  against  the  special  hollow  fitting  mentioned  before,  thus  closing  the 
valve.  When  the  boiler  pressure  decreases,  the  natural  spring  of  the  diaphragm 
opens  the  fuel  valve  and  starts  the  fire  again.  The  fuel  enters  through  the  opening 
on  the  side  and  passes  down  into  the  space  on  the  upper  side  of  the  diaphragm  and 
through  the  union  fitting  to  the  burner.  Where  a  pilot  is  u?cd,  the  fuel  valve  is  con- 
structed to  shut  off  all  the  fuel  supply  to  the  main  burner.  'Ihese  regulators  are  ordi- 
narily set  for  225  pounds  steam  pressure  and  60  pounds  air  pressure. 

Since  it  is  such  an  important  consideration  in  boiler  operation 
that  the  water  level  should  be  constantly  watched,  it  is  necessary 
that  the  water  column  should  be  placed  where  the  engineer  may 
constantly  observe  it.  Thus  it  is  that,  in  steam  carriages  it  is 
disposed  in  the  side  of  the  body  beneath  the  seat,  its  condition 
being  readily  observable  by  the  driver  by  reflection  in  a  small 


518 


SELF-PROPELLED    VEHICLES. 


mirror  set  to  one  side  of  the  dashboard.  Lamps  are  also  ar- 
ranged behind  it,  so  that  the  level  of  the  water  may  be  observed 
at  night. 

The  water  glass  also  gives  information  on  the  condition  of  the 
water  within  the  boiler,  as  when  oil  or  scum  has  collected  on  the 
surface,  causing  foaming. 


FIG.  376. 


FIG.  377. 


FIG.  378. 


FIG.  376. — The  Seabury  water  gauge.  This  device  Is  designed  to  with- 
stand any  pressure  possible  with  fire  tube  boilers.  Observation  of 
the  water  is  through  a  series  of  bull's  eyes  of  Scotch  glass  one  inch 
thick,  fitted  into  the  casting  with  two  packing  rings  and  retained 
by  a  brass  screw  ring.  The  shape  of  the  glass  is  such  that  the 
water  appears  a  deep  black  as  it  comes  over  the  bulls'  eyes,  the 
empty  compartment  above  the  water  appearing  white,  showing  the 
water  level  at  a  glance. 

FIG.  377. — Klinger  replex  water  gauge  with  piston  glass  one-half  inch 
in  thickness.  Owing  to  the  peculiar  shape  of  the  observation  glass, 
the  water  appears  black  while  the  steam  shines  with  a  silvery 
lustre.  By  removing  the  gauge  cock  at  the  bottom  and  the  cap  at 
the  top  the  inside  surfaces  may  be  cleaned. 

FIG.  378. — A  water  column  with  try  cocks  for  ascertaining  the  water 
level  in  the  boiler.  In  operation,  the  cocks  should  be  only  partially 
opened  otherwise  the  water  will  be  raised  in  the  column  which 
will  show  a  false  level. 


Troubles  with  the  Water  Glass.— Troubles  with  the  waters 
glass  that  must  be  constantly  guarded  against  are  stoppage  by 
sediment  and  the  breaking  of  the  glass  tube.    The  former  diffi- 
culty may  generally  be  remedied  by  closing  the  lower  cock  and 
allowing  the  steam  from  the  upper  one  to  blow  through  the 


BOILER  ATTACHMENTS  AND  AUTOMATICS.  519 

drain  cock  shown  at  the  bottom.  In  case  the  glass  tube  be 
broken  it  is  necessary  only  to  close  both  cocks,  and  insert  a  new 
tube  in  the  collars,  having-  first  removed  the  nuts  and  packings  at 
top  and  bottom.  In  order  to  obviate,  as  far  as  possible,  breakage 
of  the  glass  it  is  necessary  to  avoid  too  sudden  changes  of  tem- 
perature in  the  column,  when  first  opening  the  cocks,  after  get- 
ting up  steam. 


FIGS.  379,  380.-Dial  and  Interior  View  of  the  "American"  Duplex  Combined 
Steam  and  Air  Pressure  Gauge  for  Use  on  Steam  Carriages.  The  dial 
has  two  hands;  one  of  them  attached  to  a  sleeve  which  works  over  the 
spindle  carrying  the  other,  in  the  same  manner  as  the  two  hands  of  a 
clock  are  hung.  As  may  be  readily  understood,  the  two  hands  work 
in  opposite  directions,  one  clockwise,  the  other  counter-clockwise,  from 
zero  to  maximum  on  their  respective  scales.  The  sectional  view  shows 
the  mechanism  by  which  this  result  is  accomplished:  two  separate  in- 
lets, for  steam  and  air,  respectively;  two  distinct  flattened  and  curved 
steel  tubes,  each  attached  at  its  end  by  a  link  to  a  lever  and  toothed 
Sector  working  on  the  toothed  pinion  concentric  with  the  pivot  of  one  of 
the  hands.  The  two  flattened  tubes,  of  course,  have  different  tensile 
ratios,  causing  them  to  tend  to  straighten  at  different  pressures.  Hence 
the  steam  hand  records  a  maximum  pressure  of  240  pounds,  while  the  air 
hand  records  a  maximum  pressure  of  100  pounds. 

Most  of  the  water  glasses  used  on  steam  carriage  boilers  have 
self-closing  valves,  which  operate  to  prevent  the  escape  of  steam 
in  case  the  glass  is  broken.  In  the  use  of  these  valves  particular 
care  is  needed,  since  they  are  very  liable  to  be  clogged  with  sedi- 
ment or  incrustation,  causing  false  indications  of  the  water  level 
and  enabling  the  boiler  to  be  burned  out  before  the  driver  knows 
that  anything  is  wr~mg.  Several  carriage  owners,  in  the  writer's 
experience,  have  had  these  valves  removed,  and  contented  them- 
selves with  closing  the  cocks  every  time  the  glass  is  broken.  This 
may  be  a  rather  exceptional  experience,  but  it  is  extremely  de- 


520  SELF-PROPELLED    VEHICLES. 

sirable,  if  not  imperative,  to  verify  the  water  glass  reading  by  the 
try-cocks  before  starting  the  carriage. 

The  water  glass  is  an  important  piece  of  mechanism,  and  can- 
not be  too  closely  observed  and  cared  for.  Skilled  engine  drivers 
take  its  record  constantly,  and  so  very  important  is  it  that  no 
error  regarding  the  water  level  should  be  made  that  some  in- 
ventors have  proposed  using  colored  floats  to  attract  the  driver's 
eye,  and  enables  readier  reading  of  the  record.  A  supply  of  glass 
tubes  should  always  be  kept  on  hand  in  a  steam  carriage  so  that 
breakage  may  be  immediately  repaired.  Also,  every  possible  pre- 


FIG.  381. — A  steam  pressure  gauge  for  use  with  flash  boilers.  It 
is  constructed  for  indicating  pressures  tip  to  1,200  pounds  to  meet 
the  operative  conditions  of  the  flash  boilers  which  carry  much 
higher  steam  pressure  than  the  ordinary  tubular  boiler. 

caution  should  be  adopted  to  prevent  the  accumulation  of  sedi- 
ment that  might  obstruct  the  free  passage  of  the  water  into  the 
glass.  It  is  well  to  clear  the  tube  by  flushing  with  steam  at  fre- 
quent periods. 

The  Steam  Gauge. — As  a  means  of  determining  the  power 
output,  a  steam  gauge  is  attached  to  all  well-appointed  boilers, 
f  his  device  indicates  on  a  dial  the  degree  of  pressure  generated 
within  the  boiler.  Steam  gauges  are  constructed  with  one  of  the 
two  varieties  of  internal  mechanism  In  the  first  variety  the  steam 
bears  upon  a  diaphragm,  regulated  to  yield  in  proportion  to  the 
pressure  exerted.  The  second  variety  operates  through  the  ten- 
dency of  a  flattened  and  bent  metal  tube  to  straighten  out  under 
pressure  of  the  steam  or  gas  within  it.  As  shown  in  an  accom- 
panying figure,  a  tube,  flattened  to  an  ellipsoidal  cross  section,  is 


BOILER  ATTACHMENTS  AND  AUTOMATIC  DEVICES.  52] 

connected  by  one  end  to  a  steam  pipe  leading  direct  from  the 
boiler.  When  the  cock  is  opened,  steam  is  admitted  to  the  tube, 
its  pressure  tending  to  change  the  flat  section  to  one  more  neany 
round,  and  in  the  process  causing  the  tube  to  begin  uncoiling  it- 
self in  the  direction  of  a  straight  line  conformation.  Hence  the 
other  end  of  the  tube,  attached,  as  shown,  to  a  link  connected  to 
a  lever  bearing  a  toothed  segment,  tends  to  move,  causing  the 
link  to  move  the  lever. 


FIGS,  382  and  383. — Two  views  of  a  type  of  safety  valve  suitable  for  use 
on  fire  tube  boilers  which  furnish  steam  at  moderate  temperatures. 
A  snap  lever  is  provided  as  shown  for  holding1  valve  open.  When 
getting  up  steam  the  lever  is  turned  to  the  vertical  position  fig.  382. 
This  opens  the  valve  which  should  remain  in  this  position  until  all 
the  air  is  expelled  from  the  boiler  and  s*eam  begins  to  issue  through 
the  opening  when  the  valve  should  be  closed  by  turning  the  lever  to 
the  horizontal  position  as  shown  in  fig.  383. 

Safety  Valves;  Construction,  Theory  and  Operation. — Ex- 
plosion in  a  steel-shell,  copper-flued  carriage  boiler  is  very  nearly 
impossible,  and  with  moderate  care  and  watchfulness  the  burning 
out  or  collapse  of  the  tubes  can  be  prevented. 

The  unskilled  engine-driver  is  amply  protected,  if  he  only  ex- 
ercise reasonable  prudence  by  the  automatic  burner  regulator,  the 
automatic  low  water  alarm,  the  water  glass  and  steam  gauge  in 
plain  sight,  and  lastly  by  a  safety  valve  adjusted  to  blow  off  at  the 
proper  pressure. 


523  SELF-PROPELLED    VEHICLES. 

A  safety  valve  is  simply  a  valve  of  ordinary  description,  ar- 
ranged to  close  a  steam  pipe  outlet,  under  pressure  of  a  weight 
or  spring. 

The  safety  valves  used  on  steam  carriages  are  constructed  on 
the  same  general  principles  as  any  of  the  spring  valves  used  on 
locomotives,  or  other  boilers.  They  are  usually  known  as  "pop" 
valves,  from  the  fact  that  the  steam  in  lifting  the  valve  from  its 
seat  usually  makes  a  "pop"  or  sudden  detonation.  As  a  usual 
thing  carriage  valves  are  adjusted  to  a  fixed  pressure,  which  is 
never  disturbed. 


FIG.  384. — A  pop  safety  valve  designed  especially  for  use  with  super- 
heated steam.  The  spring,  as  is  shown  in  the  figure,  is  not  enclosed 
and  is  therefore  protected  from  the  high  temperature  of  the  steam. 
This  is  necessary  as  intense  heat  soon  takes  the  temper  out  of  the 
spring  and  destroys  its  elastic  properties. 

The  Blow -Off  Cock. — This  is  an  important  attachment  of  all 
boilers,  furnishing  a  ready  means  of  removing  the  water  from  the 
boiler  under  pressure  of  its  own  steam,  which  is  called  "blowing- 
off."  It  is  also  used  in  some  carriages  for  attaching  a  hose  to 
fill  the  boiler  at  starting,  or  for  injecting  water  for  cleaning  the 
interior.  It  is  usually  closed  with  a  box  nut  for  receiving  a 
wrench,  but  sometimes  by  a  cock,  as  in  large  boilers. 


CHAPTER  THIRTY-NINE. 


STEAM   SYSTEMS. 

Types  of  Power  Plants. — In  the  generation  and  application  of 
steam  as  a  motive  power  for  automobiles,  numerous  combinations 
of  engines  and  boilers  of  different  types  have  been  tried,  together 
with  varied  methods  for  securing  automatic  control  of  the  fuel 
and  feed  water. 

These  numerous  steam  systems,  may  be  classified  in  several 
ways,  as  follows: 

I.  With  respect  to  the  method  of  generating  the  steam  as: 

a.  By  shell,  water  tube  or  semi-flash  boilers,  carrying  a  water 
level,   and    furnishing   steam   at    medium   pressures. 

b.  By  flash  generators,  which  do  not  carry  a  water  level,  fur- 
nishing steam  at  high  pressures  and  with  considerable  de- 
gree of  superheat. 

NOTE. — The  terms,  medium  pressures  and  high  pressures  are  used  only  in  a 
relative  sense.  All  steam  pressures  carried  on  automobiles  are  high  when  com- 
pared to  those  in  use  for  other  requirements.  For  instance,  side  wheel  steamboats 
run  with  25  to  50  Ibs.  steam,  Corliss  engines,  50  to  150  Ibs.,  locomotives,  150  to 
225  Ibs.,  triple  expansion  marine  engines,  175  to  300  Ibs.  For  automobile  work, 
300  to  500  Ibs.  may  be  called  medium  pressures  and  500  to  1000  Ibs.,  high  pressures. 
A  steam  gauge,  registering  up  to  1200  Ibs.  is  shown  in  Fig.  381. 

2..  With  respect  to  the  manner  of  working  the  steam  in  the 
engine  as : 

a.  Simple   (sometimes  called  high  pressure)  ; 

b.  Compound  or  two  stage  expansion. 

3.  With  respect  to  the  disposition  of  the  exhaust  steam  from 
the  engine,  as: 

a.  Non-condensing; 

b.  Condensing. 

4.  With  respect  to  the  structural  features  of  the  engine,  as: 

a.  Single   acting; 

b.  Double  acting; 

c.  Duplex    (two  simple  cylinders)  ; 

d.  Multi-cylinder. 

523 


524 


SELF-PROPELLED   VEHICLES. 


Of  the  numer- 
ous combinations 
possible  with  the 
different  types  of 
engines  and  boil- 
ers, there  are  three 
which  are  in  gen 
eral  use : 

i.  A  shell  boiler 
with  duplex  en- 
gine operating  at 
medium  pressures. 

i.  A  semi-flash 
boiler  with  com- 
pound condensing 
engine  operating 
at  medium  pres- 
sures. 

3.  A  flash  boiler 
with  compound 
condensing  engine 
operating  at  high 
pressures. 

These  three  sys- 
tems will  be  ex- 
plained by  de- 
scribing the  ope- 
ration of  three 
well  known  steam- 
ers, viz.: 

1.  The  Stanley; 

2.  The  Lane ; 

3.  The  White. 

Before  explaining 
the  operation  of  the 
White  Steamer,  a 
short  description  will 
be  given  of  a  system 
devised  in  1889,  by 
Serpollet — the  pio- 
neer in  the  field  of 
flash  steam  genera- 
tion. 


STEAM  SYSTEMS. 


525 


The  Stanley  System. — The  Stanley  steamer  is  propelled  by  a 
two  cylinder,  double  acting,  high  pressure  steam  engine  of  the 
locomotive  type,  with  plain  D-slide  valves  operated  by  the  familiar 
link  motion  valve  gear.  Steam  is  supplied  by  a  fire  tube  boiler. 
Both  the  engine  and  boiler  are  illustrated  and  described  in  Chap- 
ters thirty-five  and  thirty-six. 

Automatic  devices  are  incorporated  in  the  system  which  control 
the  fuel  and  feed  water  supply. 

Fuel  Connections. — Gasoline  is  carried  in  a  tank  under  no 
pressure.  From  this  tank  it  is  pumped  as  used  to  a  receiving 
reservoir,  consisting  of  two  small  pressure  tanks  situated  side  by 


fl 

c 


¥ 

Flo.  388. — The  Stanley  gasoline  pressure  tanks.  A,  is  the  pipe  connecting  the  two  tanks; 
B,  the  pipe  through  which  gasoline  is  pumped;  C,  the  air  valve  through  which  air  is 
pumped  with  the  hand  air  pump ;  D,  a  valve  for  drawing  gasoline  out  of  the  tank  when 
desired. 

side,  so  piped  that  the  bottom  of  one  is  connected  with  the  top  of 
the  other,  as  shown  in  fig.  386.  The  main  tank,  pressure  tanks 
and  various  pipes  and  connections  comprising  the  fuel  system  is 
shown  in  the  diagram  fig.  385.  The  operation  is  as  follows :  As- 
suming the  pressure  tanks  to  be  empty,  gasoline  is  pumped  by  the 
hand  pump  until  the  pressure  gauge  registers  between  ten  and 
fifteen  pounds. 

The  effect  of  this  is  to  nearly  fill  pressure  tank  number  two  with  gaso- 
line, the  air  in  this  tank  being  forced  by  the  gasoline  into  tank  number 
one  and  is  compressed  with  the  resulting  pressure  as  indicated  by  the 
gauge. 


526 


SELF-PROPELLED   VEHICLES. 


The  pressure  in  tank  one  is  further  increased  by  attaching  the 
hand  air  pump  to  the  air  valve  and  pumping  till  the  gauge  in- 
dicates eighty  or  ninety  pounds  which  is  the  working  pressure. 

If  the  fire  were  now  lighted,  and  allowed  to  burn  for  some  time,  the 
gasoline  pressure  would  gradually  drop.  In  this  case  it  is  to  be  raised 
again  by  additional  use  of  the  hand  pump. 

With  steam  up  and  the  car  running,  the  gasoline  is  supplied 
by  the  power  gasoline  pump  operated  by  the  engine.  This 
pump  being  proportioned  to  deliver  an  excess  supply  of  fuel, 
an  automatic  relief  valve  is  provided,  adjustable  as  to  pressure, 
through  which  the  excess  passes  back  into  the  main  tank. 


FIG.  387. — Stanley  steering  wheel,  with  hands  showing  how  the  throttle 

lever    is    lightly    gripped    in    the    fingers    without    moving    the    hand 

from    the    wheel. 
FIG.  388. — View   of  Stanley    steering  wheel,   showing  the   single  throttle, 

locked    bv   its   locking  screw,   and   the   by   pass  lever  which   controls 

the  supply  of  water  to  the   boiler. 

The  air  in  the  pressure  tank  will  be  gradually  absorbed,  and 
more  will  occasionally  have  to  be  supplied  by  the  hand  pump. 
The  need  of  this  will  be  indicated  in  two  ways:  i,  when  running, 
the  hand  on  the  pressure  gauge  will  be  seen  to  vibrate,  and  2, 
when  standing  with  the  pilot  burning,  the  pressure  will  drop 
rapidly,  owing  to  too  little  air  for  expansion. 

To  be  certain  the  drop  in  pressure  is  due  to  want  of  sufficient  air,  and 
not  to  a  leaky  automatic,  the  latter  is  cut  out  by  closing  the  pressure  re- 
taining valve.  If  now,  the  pressure  continue  to  fall  rapidly,  the  cause 
is  insufficient  air  in  the  pressure  tank. 


STEAM  SYSTEMS.  537 

Water  Connections. — The  system  of  pumps  and  piping  for  the 
feed  water  supply  is  shown  in  fig.  390.  There  are  two  power 
pumps,  one  hand  pump,  by-pass  valves  and  a  water  indicator. 

The  two  power  pumps  work  continuously  when  the  car  is  run- 
ning and  have  a  capacity  sufficient  to  supply  the  boiler  when 
running  up  hill  or  over  bad  roads.  Hence,  they  must  of  necessity 
pump  too  much  water  when  the  car  is  operated  on  good  roads. 
To  prevent  the  boiler  filling  with  water  under  these  conditions,  a 
by-pass  valve  operated  by  hand  is  provided  which  when  open, 
allows  the  water  from  the  pumps  to  be  returned  to  the  tank  in- 
stead of  into  the  boiler.  By  hand  control  of  this  valve  the  de- 
sired water  level  is  maintained  in  the  boiler.  The  pumps  are  so 


FIG.  389. — Water,  gasoline  and  cylinder  oil  pumps  of  the  Stanley  car.  As 
shown  in  the  illustration,  the  four  plungers  form  one  moving1  part. 
The  two  large  Dumps  are  for  water,  one  or  both  of  which  may  be 
by-passed  by  the  lever  on  the  steering  wheel. 

connected  that  one  or  both  may  be  by-passed,  the  by-pass  valves 
being  operated  by  a  lever  on  the  steering  wheel. 

If  the  pumps  become  air  bound,  that  is,  if  the  pump  cylinders 
and  valves  become  filled  with  air  it  will  fail  to  deliver  water. 

The  reason  for  this  is  that  the  air  will  be  simply  compressed  and  re- 
expanded  as  the  plunger  goes  in  and  out,  hence,  no  water  would  enter 
the  pump. 

To  remedy  this,  it  is  only  necessary  to  open  the  by-pass  for  a  moment 
The  pump  being  thus  relieved  of  boiler  pressure,  the  air  will  be  pumped 
out  through  the  by-pass  and  the  pump  will  fill  with  water  and  become 
again  operative. 

Instead  of  the  ordinary  form  of  glass  water  gauge,  a  special 
water  indicator  is  used  as  shown  in  the  diagram  fig.  391. 


528 


SELF-PROPELLED   VEHICLES. 


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STEAM  SYSTEMS. 


529 


The  construction  of  this  device  is  as  follows:  A  water  column  F  is 
so  connected  with  the  boiler  at  its  top  and  bottom,  that  the  water  will 
stand  at  the  same  level  in  the  column  as  in  the  boiler. 

Connected  with  the  water  column  at  D,  about  eight  or  nine 
inches  above  the  bottom  of  the  boiler,  is  a  casting"  which  may  be 
called  the  indicator  body,  containing  two  adjacent  chambers  G 
and  H,  one  of  which  fills  from  the  boiler  through  the  connection 
D. 

Through  the  other  chamber  the  feed  water  is  pumped,  whether 
going  to  the  boiler  or  through  the  by-pass  back  to  the  tank.  This 


Return-to  watertank 


FIG.  391. — Stanley  system  of  Indicating  water  level.  A,  is  a  blow  off  and 
try  cock;  B,  try  cock;  C,  shut  off  valve.  In  cleaning  out,  cock  C  is 
closed  and  cock  A  opened  when  steam  is  up. 

latter  chamber  may  be  called  the  water  chamber,  and  the  other 
the  boiler  chamber. 

It  is  evident,  that  the  "boiler  chamber"  will  be  filled  with  water 
provided  the  water  in  the  column  is  above  the  connection  D ; 
otherwise  it  will  be  filled  with  steam. 

The  indicator  proper  is  a  "U"  tube,  one  end  of  which  J  is  of 
metal  and  sealed  at  the  top,  and  called  the  "standpipe."  This 
end  is  inserted  some  distance  up  into  the  "boiler  chamber,"  and 
is  at  all  times  surrounded  by  either  steam  or  water. 


530  SELF-PROPELLED   VEHICLES. 

The  other  end  of  the  "U"  tube  is  a  glass  tube  K,  placed  ver- 
tically on  the  dashboard.-  This  "U"  tube  is  filled  with  water  sa 
that  the  standpipe  J  is  filled  entirely,  and  the  water  when  cold 
stands  in  the  glass  an  inch  or  two  from  the  bottom. 

The  operation  of  the  device  is  as  follows:  As  long  as  the 
chamber  G  surrounding  the  standpipe  is  filled  with  water  and  the 
feed  water  is  being  pumped  through  the  other  chamber  H,  it  will 
keep  the  water  in  the  former  chamber  comparatively  cool,  and 
also  the  water  in  the  standpipe,  and  the  water  will  remain  at  a 
low  point  in  the  glass. 

As  soon,  however,  as  the  water  gets  below  the  connection  D, 
the  "boiler  chamber"  will  fill  with  steam,  and,  as  it  surrounds  the 
"standpipe"  it  will  vaporize  some  of  the  water  in  it  and  force 
the  water  out  of  it  and  up  in  the  glass,  thus  showing  that  the 
water  level  in  the  boiler  is  below  the  indicator.  Whereupon  the 
pump  by-pass  should  again  be  closed  until  the  water  falls  in  the 
glass  again,  which  will  indicate  that  the  water  in  the  boiler  is 
above  the  connection  D  on  the  indicator. 

Usually  when  the  car  is  standing  the  indicator  will  receive 
sufficient  heat  to  throw  the  water  up  into  the  glass.  In  this  case, 
if  the  water  in  the  boiler  is  above  the  connection  D,  it  will  im- 
mediately cool  off,  and  the  water  will  drop  again  in  the  glass 
when  the  car  is  run  and  water  is  pumped  through  the  "water 
chamber." 

The  copper  tube  L,  leading  from  the  standpipe  extends  down- 
ward six  or  seven  inches  before  bending  upward  again  to  the 
water  glass  bracket,  so  that  the  hot  water  or  steam  from  the 
standpipe  will  not  pass  up  into  the  water  glass. 

Some  three  inches  below  the  connection  D,  mentioned  above 
there  is  another  connection  M  and  a  pipe  from  this  leading  up 
through  the  dashboard,  at  the  end  of  which  is  a  petcock  N,  in- 
dicated on  the  sktech.  This  is  called  the  low  water  test. 

As  long  as  the  water  covers  this  connection  this  petcock  will 
remain  comparatively  cool,  and  if  opened,  water  will  come  out. 
If,  however,  the  water  should  get  below  this  connection,  the  pipe 
will  fill  with  steam  and  the  end  will  become  burning  hot,  and 
if  the  petcock  were  opened  steam  would  come  out.  By  this 


STEAM  SYSTEMS.  531 

means  the  operator  can  determine  whether  or  not  the  water  in 
the  boiler  is  getting  near  the  point  where  the  fusible  plug  would 
melt  out. 

When  the  boiler  is  cold,  whether  or  not  it  contains  water,  the 
water  will  always  be  low  in  the  glass.  Consequently,  before  light- 
ing the  burner,  one  of  the  petcocks  should  be  opened  and  the 
siphon  valve  opened,  so  as  to  vent  the  boiler.  If  water  come 
out  of  the  petcock,  it  indicates  that  the  water  in  the  boiler  is  above 
that  point.  If  not,  it  is  below  that  point.  The  petcock  should  be 
kept  open  long  enough  to  allow  any  water  that  might  be  in  the 
tube  to  run  out,  provided  it  happened  to  be  held  there  by  capillary 
attraction  when  the  water  in  the  boiler  was  really  below  the  pet- 
cock. 

The  operator  should  never  start  the  fire  until  he  is  certain  that 
there  is  water  in  the  boiler. 

The  connection  betwen  the  bottom  of  the  boiler  and  the  bottom 
of  the  water  column  must  be  kept  clear,  otherwise  the  water 
might  remain  in  this  column,  even  if  there  were  none  in  the 
boiler. 

This  is  cleaned  by  closing  valve  C  and  opening  the  petcock  A,  when 
there  is  steam  in  the  boiler.  This  will  blow  out  any  sediment  that  may 
be  in  the  lower  end  of  the  water  column. 

If  the  water  indicator  is  to  be  used  in  freezing  weather,  a  mixture  of 
glycerine  or  alcohol  and  water,  one  to  one,  is  employed  in  the  "U"  tube 
to  prevent  freezing. 

It  is  sometimes  desirable  to  test  the  indicator  to  see  if  it  be  working 
properly.  To  do  this,  the  boiler  should  be  well  filled  with  water,  say 
considerably  above  connection  D. 

With  steam  up  and  petcock  B  opened,  hot  water  or  steam  will  flow 
through  the  boiler  chamber  of  the  indicator,  and  if  the  indicator  be 
working  properly,  the  water  should  rise  in  the  glass. 

Now,  if  petcock  B  be  closed  and  cold  water  be  pumped  through  the 
water  chamber  of  the  indicator  by  the  hand  pump,  the  boiler  chamber 
will  be  cooled  which  will  cause  the  water  to  again  fall  in  the  glass. 

The  pumping  may  be  done  with  the  by-pass  open  which  saves  pumping 
against  the  boiler  pressure. 

The  familiar  torch  method  is  followed  in  starting  the  burner, 
a  small  gasoline  torch  being  provided  for  the  purpose.  To  start 
the  fire  successfully,  both  main  burner  nozzles  and  the  pilot 
nozzle  should  be  heated  and  then  the  pilot  lighted.  To  do  this, 
the  valve  is  opened  one  turn  and  the  torch  flame  immediately 


532 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


pointed  into  the  peek  hole,  its  slide  having  been  previously  opened. 
After  the  pilot  is  lighted,  this  slide  should  be  closed  before  turn- 
ing on  the  main  fire.  The  latter  operation  should  be  performed 
by  opening  the  main  valve  slowly  so  that  the  fire  will  come  on 
gradually. 

The  Fusible  Plug. — If  the  water  in  a  fire  tube  boiler  were 
all  evaporated,  and  the  fire  kept  burning,  the  boiler  would  be- 
come so  heated  as  to  cause  it  to  leak  badly. 

•/y'/i'ary    Tfl>"of//<.    H&lte. 


"YnaJn  TVofl/e 


Tnam  Sfuiia  P-fae. 


PIG.  392. — Steam  connections  and  superheaters  of  the  Stanley  system.  The  elbows  on  the 
superhaater,  main  steam  pipe  and  fusible  fitting  are  made  on  a  taper  and  driven  through 
the  boiler  tubes.  They  are  removed  by  prying  under  the  elbow  and  hammering  at  the 
same  time. 

To  avoid  this,  the  boiler  is  equipped  with  a  fusible  plug.  When  the 
water  in  the  boiler  gets  within  three  inches  of  the  lower  tube  sheet,  the 
plug  melts,  and  the  noisy  escape  of  steam  notifies  the  operator,  who  im- 
mediately shuts  off  the  fire,  both  pilot  and  main  burner,  thus  protecting 
the  boiler  from  injury.  When  the  plug  blows  and  the  fire  is  shut  off,  it 
is  a  good  plan  to  continue  running  till  the  steam  pressure  is  so  reduced 
as  to  compel  a  halt.  The  by-pass  is  then  closed  and  water  pumped  into 
the  boiler  till  it  is  cool  enough  to  allow  the  plug  to  be  removed,  a  new 
lead  inserted  and  the  plug  replaced. 

The  pumping  may  then  be  continued  till  the  boiler  is  one-third  full  when 
the  fire  may  be  lighted.  Usually  this  can  be  done  without  reheating  the 
torch,  provided  the  renewing  of  the  plug  has  been  quickly  done.  The 
material  in  the  plug  is  common  lead  which  melts  at  6i8°Fahr. 


STEAM  SYSTEMS.  533 

The  Lane  System. — The  power  plant  of  the  Lane  steamer  con- 
sists of  the  following  elements : 

1.  Cross  compound  engine; 

2.  Condenser; 

3.  Feed  water  heater; 

4.  Semi-flash  boiler; 

5.  Control :  automatic  regulating  devices  for  fuel  and  water ; 

6.  Auxiliary  Control:  hand  regulating  devices; 

7.  Fuel  and  water  tanks  and  connections. 

The  boiler  is  designed  for  a  working  pressure  of  500  pounds, 
the  running  pressure  being  300  pounds. 

It  consists,  as  previously  described,  of  a  series  of  semi-flash  coils,  a 
separator,  and  a  fire  tube  shell,  the  combination  delivering  to  the  engine 
a  supply  of  steam  slightly  superheated  by  the  fire  tubes  which  is  favorable 
to  economical  operation. 

Fuel  Connections. — The  burner  is  started  by  the  operation  of 
one  valve.  There  is  within  the  burner  casing  an  igniting  torch 
below  the  vaporizing  tubes.  This  torch  consists  of  a  perforated 
tube  enclosed  in  an  absorbent,  non-combustible  envelope.  The 
tube  is  connected  with  a  cup  conveniently  located  outside  the 
burner. 

In  addition  to  the  valve  for  operating  the  burner,  there  is  a 
second  valve  in  the  fuel  feed  pipe,  accessible  from  the  driver's 
seat,  and  also  a  valve  for  controlling  the  pilot  light ;  these  valves 
are  used  only  occasionally. 

The  burner  is  open  */&  inch  between  the  ?•£  inch  diameter  burner  tubes, 
so  as  to  ensure  a  sufficient  supply  of  oxygen  for  complete  combustion,  and 
the  2l/2  ins.  dia.  mixing  tube  is  carried  3  ins.  outside  of  the  burner  casing 
so  as  to  cool  the  mixture  enough  to  prevent  firing  back  into  the  burner 
and  mixing  tubes. 

The  blow  out  of  the  burner  flame  is  prevented  by  reducing  the  inner 
mixing  tube  to  il/$  ms-  inside  diameter  and  by  fitting  a  cowl  closed  on 
the  top,  bottom,  front  and  outside,  air  taken  in  at  the  rear  of  the  cowl, 
which  acts  both  as  a  wind  shield  and  mud  guard. 

The  Gasoline  Tank. — The  fuel  supply  is  contained  in  a  cylin- 
drical tank  having  oval  ends.  A  tank  of  seventeen  gallons  capac- 
ity is  provided  for  the  twenty  horse  power  engine  and  one  hold- 
ing twenty-two  gallons  for  the  thirty  horse  power  engine.  A 


534 


SELF-PROPHLLED  VEHICLES. 


pressure  of  60  pounds  is  maintained  in  the  tank,  this  pressure 
being  maintained  automatically.  The  air  pump  is  located  on  the 
left  side  of  the  engine. 

The  maximum  air  pressure  available  is  determined  by  the  pump  clear- 
ance. This  clearance  space  (between  the  pump  valves)  can  be  adjusted 
through  a  considerable  range  by  a  screw  reached  from  the  outside. 

An  independent  steam  pump  is  provided  for  emergency  use. 

The  Water  Connections. — The  feed  water  to  the  boiler  is 
regularly  pumped  by  a  crosshead  pump  on  the  engine,  which  has 
a  capacity  in  excess  of  requirements,  the  level  in  boiler  being 
regulated  by  an  automatic  by  pass  connected  to  the  delivery  pipe 
from  engine  pump  which,  when  open,  allows  the  water  pumped 
to  return  to  the  tank  again,  but  if  closed  all  the  water  pumped 
must  go  into  the  boiler. 


FIG.  393. — The  Lane  water  indicator  as  it  appears  on  the  dash.  It  forms 
a  part  of  the  by  pass  apparatus  and  its  essential  feature  is  an  ex- 
pansion tube.  It  is  connected  by  pipe  to  the  boiler  at  the  desired 
water  level. 

There  is  also  for  emergency  use  an  independent  steam  pump, 
the  reserve  power  of  boiler  permitting  its  use  either  standing  or 
running,  and  a  hand  pump  under  the  foot  board. 

The  Water  Tank. — This  is  located  between  the  condenser  and 
the  boiler,  and  is  piped  to  the  engine  feed  water  pump,  the  water 
steam  pump,  and  the  water  hand  pump. 

Connection  with  the  condenser  is  near  the  top  of  the  tank  and 
a  water  overflow  pipe  three-quarter  inch  below  the  condenser 
pipe,  top  end  affords  a  steam  exit. 


STEAM  SYSTEMS.  533 

The  Water  Indicator. — This  device  for  ascertaining  the  water 
level  in  the  boiler  consists  of  a  dial  indicator  located  on  the  dash 
as  shown  in  fig.  393,  operated  by  an  automatic  by  pass  illustrated 
in  fig.  394.  Its  essential  feature  is  an  expansion  tube  which  is 
located  above  the  hood  and  in  front  of  the  dash  and  connected  by 
pipe  to  the  boiler  at  the  desired  water  level. 

If  water  in  boiler  be  below  that  point  the  expansion  tube  will  be  filled 
\vith  steam  and  being  hot  is  consequently  in  an  expanded  condition,  and  by 
suitable  mechanical  means  it  then  holds  the  by  pass  valve  shut  and  the 
indicator  hand  in  its  corresponding  position. 

When  the  water  level  in  the  boiler  rises  above  the  point  of  connection, 
the  pipe  becomes  filled  with  water  and  the  tube  cools.  It  consequently 
contracts,  opens  the  by  pass  valve,  and  moves  the  indicator  hand. 

A  second  expansion  tube  acts  from  a  lower  point  on  the  boiler  and 
moves  the  indicator  hand  still  further  around  if  the  water  level  recedes 
below  the  normal. 


FIG.  394. — The  Lane  automatic  by  pass.  This  is  operated  thermostatic- 
ally, that  is,  by  the  expansion  and  contraction  of  a  metal  rod 
brought  about  by  temperature  changes  which  depend  on  the  height 
of  the  water  in  the  boiler. 

The  Condenser. — The  exhaust  from  the  engine,  instead  of 
being  discharged  into  the  atmosphere,  as  is  done  in  the  Stanley 
system,  is  led  by  suitable  piping  to  a  condenser  in  which  it  is 
cooled,  condensed  and  returned  to  the  water  tank. 

The  compound  type  of  engine  is  especially  adapted  to  run  condensing, 
as  the  steam  is  exhausted  at  a  lower  pressure,  than  is  done  with  a  simple 
engine.  The  exhaust  steam  is  not  so  hot  and  hence,  the  proportions  of 
the  condenser  capable  of  condensing  the  steam  is  less  than  would  be  re- 
quired with  a  simple  engine. 

The  Lane  condenser  as  shown  in  fig.  395,  consists  of  five  verti- 
cal rows  of  flattened  brass  tubes  opening  into  a  top  header  to 
which  the  exhaust  is  piped,  and  to  an  unobstructed  base  cavity 
which  is  piped  to  the  top  of  the  water  tank. 


536 


SELF-PROPELLED   VEHICLES. 


The  discharge  of  this  condenser  to  the  water  tank  is  inter- 
mittent, a  quart  or  so  at  each  discharge,  from  the  base  cavity  of 
the  condenser. 

This  condenser  piping  avoids  a  water  pump  between  the  condenser  and 
the  water  tank,  though  the  bottom  of  the  condenser  is  about  30  ins.  below 
the  tank  top. 


FIG.  395. — The  Lane  condenser  for  condensing  the  exhaust  steam  from 
the  engine.  It  is  constructed  of  thin,  flat,  brass  tubes  arranged 
vertically,  with  their  edges  toward  the  front,  and  air  spaces  be- 
tween them.  They  are  all  secured  to  a  common  header  with  detach- 
able covers  at  top  and  bottom;  steam  being  introduced  in  the  top 
one  and  the  water  piped  from  the  lower  one  directly  back  to  the 
dome  of  the  tank.  There  is  a  still  larger  vent  from  the  dome  of 
tank  to  the  atmosphere  below  the  car.  There  is  no  pump  or  out- 
board relief,  the  water  being  returned  from  condenser  to  tank  by 
back  pressure,  which  rarely  exceeds  one  pound  and  is  usually  much 
less.  Inside  the  top  header  is  a  coil  for  heating  the  feed  water  on 
its  way  to  the  boiler. 

Control  System. — Before  beginning  to  raise  steam  the  driver 
tries  the  gauge  cocks  screwed  directly  into  the  boiler  shell ;  if  no 
water  shows  at  the  gauge  the  hand  force  pump  is  worked  to  fill 
the  boiler  to  the  gauge  from  the  water  tank.  There  are  3  gauge 
cocks ;  water  at  the  lower  cock  indicates  enough  to  raise  steam. 

To  raise  steam:  I,  the  air  down  draft  damper  on  top  of  the 
hood  is  opened  to  permit  a  free  passage  of  air  to  the  burner ;  2,  a 


STEAM  SYSTEMS.  537 

door  in  the  side  of  the  hood  at  the  bottom  of  the  boiler  is  opened, 
giving-  access  to  the  "heater  cup"  into  which  about  a  fluid  ounce 
of  alcohol  is  poured,  this  going  to  a  horizontal  pipe,  perforated 
and  asbestos  clothed,  placed  below  the  gasoline  vaporizing  tube ; 
3,  the  asbestos  pipe  clothing  alcohol  wick  is  lighted,  and  4,  a  hand 
needle  valve  between  the  vaporizer  and  the  burner  middle  mixing 
tube  is  opened,  to  permit  the  gasoline  vapor  injection  to  the  burner 
main  middle  tube. 

As  soon  as  the  gasoline  vapor  begins  to  escape  from  the  small  holes 
in  the  tops  of  the  burner  tubes  it  is  fired  by  the  flame  of  the  heating  tube 
and  everything  is  left  as  it  is  until  the  steam  gauge  shows  300  Ibs.,  and 
the  car  is  ready  to  run. 

The  operation  of  getting  up  steam  usually  takes  about  ten  minutes. 

As  soon  as  steam  is  raised,  the  top  air  damper  is  closed  and 
steam  is  turned  on  to  the  .forced  draught  ejector,  which  sucks  air 
up  through  the  burner  and  boiler  flues  and'  then  forces  the  pro- 
duct of  combustion  down  to  the  open  lower  end  of  the  vertical 
down  draft  tube,  which  is  about  5  ins.  diameter  and  extends  down- 
ward to  about  the  bottom  of  the  burner. 

The  engine  can  be  started  by  moving  the  ratchet  retained  hand 
lever  on  top  of  the  steering  wheel,  as  soon  as  there  is  steam  pres- 
sure enough  in  the  boiler,  and  after  the  engine  begins  working 
the  water  level  and  fuel  supply  are  automatically  controlled. 

There  are  two  vertical  levers:  the  latched,  outside  one,  is 
pushed  forward  to  apply  the  external  rear  hub  drum  brake  bands 
through  a  full  length  evener.  The  latched,  inside  hand  lever, 
works  the  tumbling  shaft  to  make  the  link  valve  motion  give  an 
earlier  or  later  cut  off,  and  the  reverse. 

The  forced  draft  steam  valve  is  opened  and  closed  by  a  small  T-handle 
on  top  of  the  steering  wheel. 

There  is  one  pedal  on  the  foot  board,  which  is  pushed  forward  to  apply 
the  balance  gear  drum  brake  band,  ordinary  brake. 

A  plunger  pedal  at  the  left  of  the  steering  column  is  depressed  to  change 
the  engine  from  compound  to  simple,  the  engine  returning  to  compound 
as  soon  as  this  plunger  pedal  is  released. 

The  stop  valve  between  the  boiler  and  throttle  is  opened  and  closed  by 
a  wooden  hand  wheel  at  the  front  left  of  the  foot  board. 

A  small  handle  in  the  middle  of  the  front  board  rear  face  controls  the 
boiler  water  supply  independently. 

A  long  vertical  glass  tube  at  the  right  of  the  front  board  shows  the 
water  level  in  the  tank. 

The  large,  hand  worked  plunger  glass  oil  cup  at  the  top  left  of  the  front 
board,  supplies  lubricating  oil  to  the  two  independent  steam  pumps. 


838 


SELF-PROPELLED  VEHICLES.. 


The  Auxiliary  Control  System. — This  is  operated  by  eight 
valve  handles  as  shown  exposed  in  fig-.  396  by  the  removal  of  the 


cover. 


It  should  be  understood  that  this  auxiliary  control  system  has  nothing 
to  do  with  the  regular  control  of  the  car,  as  handled  by  the  driver  when 
running  on  the  road,  but  simply  controls  the  auxiliary  pump  driving  and 
oiling,  supplying  steam  driven  water  and  air  pumps  and  directing  the 
hand  pump  oil  supply. 


Flo.  396. — The  Lane  System,  engine  placing  and  control,  footboards  and  auxiliary  control 
cover  removed.  The  illustration  shows  the  inclined  engine  cylinders,  the  independ- 
ent steam  water  pump  and  the  hand  water  pump,  last  resort  for  supplying  the  boiler 
water.  The  hand  cylinder  and  steam  pump  oiler,  a  glass  cup  with  a  nand  force 
pump  is  shown  at  the  upper  left  of  the  front  board  real  face.  Next  to  the  right  is 
the  dial  indicator  which  shows  the  boiler  water  level.  The  next  dial  shows  the  air 
pressure  in  the  gasoline  tank,  and  the  third  dial  is  the  steam  gauge.  The  glass  tube 
at  the  right,  TG,  shows  the  water  level  in  the  water  tank.  The  auxiliary  control 
cover,  when  removed,  discloses  8  handles,  top  left  handle  opens  the  hand  oil  pump 
to  the  independent  steam  water  and  air  pump  steam  cylinders,  the  top  row  middle 
handle  works  the  compressed  air  valve  to  either  send  air  to  the  gasoline  tank  or  to 
the  tire  inflating  tube,  or  to  open  air  if  tire  inflating  hose  be  removed.  The  right 
hand  top  valve  is  the  steam  pump  steam  admission.  The  left  handle  in  the  middle 
row  opens  the  oil  lead  from  the  hand  pump  to  the  engine  steam  chest.  The  middle 
handle  controls  the  stop  valve  in  the  line  from  the  engine  driven  air  pump  to  the 
gasoline  tank.  The  right  handle  in  the  low  line  opens  steam  to  the  steam  water 
pump.  The  fusible  plug  screw  T-handle  is  seen  at  the  left  of  the  front  board  auxil- 
iary control  opening.  The  metal  wheel  just  below  works  the  sto£  valve  between 
the  fusible  plug  and  the  steam  boiler.  SPP  is  a  plunger  pedal  which  is  depressed 
to  change  the  engine  from  compound  to  simple.  BP  is  too  ordinary  brake  pedaL 


'STSAM  SYSTEMS. 


539 


The  emergency  water  and  air  pumping,  when  required,  is  done  by 
independent  steam  pumps  the  air  pump  being  available  for  both  tank  pres- 
sure and  tire  inflating,  so  that  the  driver  is  relieved  from  all  pump  work. 

Cycle  of  Operation. — With  steam  up  and  the  car  running,  the 
feed  pump  on  the  engine  forces  water  to  the  boiler. 

The  water  passes,  first  through  the  feed  water  heater  located  in  the 
top  of  the  condenser,  where  it  absorbs  heat  from  the  exhaust  steam,  be- 
fore entering  the  boiler  preheating  coils. 

In  passing  through  the  preheater  coils,  the  temperature  of  the  water 
is  considerably  raised,  and  it  is  discharged  from  these  coils  into  the 
separator,  as  water  and  steam. 


FIG.  397.— The  Serpollet  Water  and  Fuel  Feed  System.    The  method  of  hang- 
ing the  stepped  cam  controlling  the  pump  stroke  may  be  here  understood. 

The  water  is  led  from  the  separator  to  the  bottom  of  the  tubular  shell 
and  the  steam  to  the  top. 

Saturated  steam  is  taken  from  the  top  of  the  shell,  whence  it  is  de- 
livered to  the  engine  in  a  slightly  superheated  state. 

The  steam  after  working  expansively   in  the   high   pressure 
cylinder  of  the  engine  approaching  a  state  of  saturation,  is  ex- 


540 


SELF-PROPELLED   VEHICLES. 


hausted  into  a  larger  or  low  pressure  cylinder  where  it  is  again 
expanded  and  finally  exhausted  into  the  condenser;  here  it  is 
practically  all  condensed  under  ordinary  conditions  and  the  water 
returned  to  the  tank  to  again  begin  the  cycle  as  just  described. 

When  the  engine  is  heavily  loaded  as  in  ascending  steep  hills,  the  con- 
denser may  be  overtaxed  and  only  condense  a  portion  of  the  steam.  This 
together  with  other  losses,  such  as  leaks  from  the  stuffing  boxes,  etc., 
have  to  be  made  up  by  replenishing  the  water  supply  in  the  tank. 

The  efficiency  of  the  condenser  depends,  largely  on  the  temperature 
of  the  atmosphere.  This  is  clearly  indicated  by  the  difference  in  its  opera- 
tion in  winter  and  summer. 


PIG.  398.— Serpollet's  Fuel  and  Water  Pumps.     The  water  pump,  a,  and  the 
fuel  pump,   6,  are  operated  from  the  lever,  c.     This  is  given  an  up-and- 
down  movement  by  the  link,   d,   whose   stroke  is  varied   by   the  stepped 
cam,  f,  on  which  bears  the  roller,  e,  on  the  rod  pivoted  at  i.     The  rotary 
•    movement  of  the  cam  shaft,  g,  is  imparted  by  the  spur  wheel,  h. 

Flash  Steam  Generation:  The  Serpollet  System. — The  flash 
method  of  producing  steam,  was  introduced  by  Serpollet  in  1889. 
He  invented  an  instantaneous  generator  which  is  described  in  the 
chapter  on  boilers. 

The  successful  operation  of  a  flash  generator  depends  largely 
on  the  design  of  proper  automatic  devices  and  connections  for 
regulating  the  supply  of  feed  water  and  fuel.  The  office  of  these 
automatics  is  to  so  control  the  generation  of  steam  that  a  supply, 
varying  to  meet  the  engine  demands,  may  be  had  at  a  certain  pre- 
determined pressure  and  degree  of  superheat. 


STEAM  SYSTEMS. 


541 


It  is  possible  to  maintain  the  feed  at  the  proper  rate  and  quan- 
tity by  automatic  pressure  regulators,  such  as  are  used  in  connec- 
tion with  steam  carriage  burners,  or  else  by  some  system  of  uni- 
form regulation  for  fuel  and  water  pumps. 

The  latter  theory  was  adopted  in  the  Serpollet  system  being 
worked  out  by  Gardener. 

As  shown  in  the  diagram,  the  fuel  is  fed  to  the  burner,  and  the  water 
to  the  boiler,  through  pumps,  both  of  which  are  operated  from  the  same 
shaft.  The  fuel  pump  is  smaller  than  the  water  pump  and  its  stroke  is 
also  shorter,  as  is  obviously  necessary.  This  is  accomplished  by  the  use 


FIG.  399.— The  "Safety  Valve,"  or  Automatic  By-Pass  Regulator  of  the  Ser- 
pollet Boiler  Feed  System.  The  steam,  admitted  through  the  tube,  a, 
after  it  has  reached  a  certain  pressure,  opens  the  valve,  6,  compressing 
the  spring,  c.  By  this  action  the  rod,  d,  forces  up  the  valve,  e,  and  the 
spring,  f,  thus  enabling  the  water  from  the  pump  to  pass  from  the  pipe, 
g,  through  the  pipe,  ft,  to  the  water  tanK. 

of  a  stepped  cam,  consisting  of  a  row  of  eccentric  discs,  of  varying  ec- 
centricity, which,  placed  upon  the  rotating  shaft,  may  be  slid  in  either  di- 
rection, thus  varying  the  lift.  By  shifting  the  cam  inward  toward  the 
driving  spur  the  strokes  of  both  oil  and  water  pumps  may  be  varied  from 
zero  to  maximum ;  the  cam  surface  being  efficient  in  giving  a  greater  or 
shorter  inward  stroke,  and  in  permitting  an  outward  stroke  of  equal  length 
under  stress  of  the  spiral  spring  attached  below  the  pump  operating  lever. 


542 


SELF-PROPELLED  VEHICLES. 


A-Power  Feed  Water  Pump 

B-Peed  Water  Heater 

C-Connection  for  Boiler  Peed.  Water 

Regulator  and  Bottom  Blow  Down 
D-Boiler  Heed  Check  Valve 
K-Water  Regulator  Gauze  Strainer 
F-Globe  Valve 
G-lioik-r  Blow  Down 

H  Hy-pass  Line  to  Water  Regulator  Valve 
I-Water  Regulator  Valve 

By-pass  Connection 
J-Water  Regulator  Valve 
K-Water  Regulator  Valve  Cam 
L-Water  Regulator  Valve  Cam 
M-Water  Regulator  Le«tr 
N- Water  Regulator  Expansion  Tube 
O-Waler  Kegulator  Lever  Btace 
P-Water  Regulator  Water  Column 
Q- Water  Regulator  Pet  Cock 
R>Top Connection  for  Gauge  Glass  if  Desired 
S-Waier  Regulator  ,, 

Water  Column  Connection 
T-Connection  for  Steam  Gauge,  Pumps,  Etc. 
U-Steam  line  to  Fuel  Kegulator 
V-ConnectioB  for  Pop  Safety  Valve,  Etc. 
W -Steam  Connection  for  Engine 


a-Maln  Puel  Tank      b-Globe  Valve 

c-Gauze  Strairitr        d-Hand  Puel  Pump 

e-Power  Fuel  Pump 

f-Connection  to  Automatic  Puel  Feed 

g-Check  Valve 

h-Connectipu  to  Puel  Gauge 

i-Automatic  Fuel  Feed 

j-By-pass  Valve  of  Automatic  Fuel  Peed 

k-Keturn  Line  of  Leakage  by  Piston 

1-Fuel  By-pass  Line 
m-Return  Line  to  Tank  of  k  and  i 

n-Globe  Valve       ,     . 

o-Branch  f-uel  Line  to  Pilot 

p-C^eck  Valve  with  Check  Removed  and 
Sp.on.ee  in  its  place  for  a  Dirt  Strainer 

q-Pilot  Valve          '    r-Pilot  Vaporizer 

s-Pilot  Nozzle  t-Pilot  Box 

n-Screw  for  Holding 

Pilot  Vaporizer  Straight 

v-Fuel  Line  to  Main  Burner 

w-Automatic  Hue!  Regulator 

z-Main  Burner  Valve 

y-Main  Burner  Vaporizer 

z-Main  Burner  Hlbow 
ai-Maiti  Burner  Nozzle 
a2-Wain  Burner  Mixing  Tube 
as-Slide  Over  Hole  for  Observing  Fire 


Flo.  400. — The  Ofeldt  system  of  automatic  fuel  and  water  regulation  as  applied  to  th« 
Ofeldt  boiler.  The  operation  of  the  water  regulator  is  explained  under  Fig.  374. 
The  automatic  fuel  feed  i,  consists  of  a  brass  tube  four  inches  in  diameter  by  eighteen 
to  thirty-six  inches  long,  capped  on  one  end  and  plugged  on  the  other.  Inside  this 
tube  is  a  piston  and  a  spiral  spring,  the  latter  being  the  whole  length  of  the  tube.  A 
safety  valve  is  attached  to  the  by-pass  line,  which  can  be  set  to  carry  whatever 
pressure  is  desired.  A  connection  is  also  made  to  permit  whatever  fuel  leaks  by  the 
piston  to  return  to  the  tank.  A  hand  fuel  pump  d,  is  provided  for  use  when  starting 
the  burner.  The  operation  is  as  follows:  Fuel  is  forced  by  a  fuel  pump  e,  on  crosshead 
of  engine  or  else  where  through  connection  f  to  the  cylinder  and  against  the  piston, 
which  in  turn  compresses  the  spring  and  the  latter  gives  the  pressure  to  the  fuel. 
The  fuel  is  forced  to  the  burner  through  the  line  containing  valve  n.  A  safety  valve 
jt  can  be  adjusted  to  carry  any  pressure  desired;  i,  is  the  overflow  connection  to  tank. 


STEAM  SYSTEMS.  543 

These  operations  may  be  readily  understood  by  a  study  of  Fig.  397,  which 
is  sketched  from  the  actual  machine. 

The  liquid  fuel  and  the  water,  being  thus  varied  in  the  amounts  given 
forth  by  the  pumps,  are  forced,  the  one  into  the  vaporizing  tube,  passing 
over  the  burner,  the  other  into  the  flattened  and  nested  tubes  of  the  gen- 
crator.^  By  this  means  the  heat  is  increased  in  ratio  with  the  quantity  of 
water  injected,  and  the  working  pressure  may  be  regulated  to  any  desired 
limit.  When,  however,  the  pressure  has  arisen  above  a  certain  fixed 
point — it  is  generally  fixed  at  about  355  pounds  per  square  inch — it  is  able 
to  open  the  spring  safety  valve,  k,  shown  attached  to  the  steam  pipe, 
fig.  399,  thus  also  opening  the  by  pass,  m,  so  that  the  water  from  the 
feed  pump  is  thrown  back  into  the  tank. 

The  water  from  the  pump  may  be  forced  through  the  spring  valve, 
instead  of  into  the  generator,  by  the  closing  of  a  check  valve  at  P,  under 
steam  pressure. 

The  connections  may  be  readily  understood  from  the  diagram,  which 
also  shows  a  hand  operated  pump  for  making  the  initial  injection  of  water 
into  the  generator  tubes  previous  to  starting  .the  engine. 

The  construction  and  operation  of  the  automatic  by  pass  regulator,  or 
"safety  valve,"  may  be  understood  from  Fig.  399. 

Strictly  speaking,  a  flash  generator  needs  no  safety  valve,  but  its  opera- 
tion demands  some  method  of  preventing  flooding  when  the  pressure  is 
high  enough. 

The  White  System. — The  method  of  regulating-  the  supply  of 
water  and  fuel  to  the  steam  generator  of  the  White  steamer, 
presents  an  inter-relationship  of  water,  gasoline  and  steam  that 
is  highly  interesting,  exceedingly  unique,  and,  as  demonstrated 
daily  by  the  cars,  is  most  satisfactory.  Broadly  speaking,  the 
operation  of  the  system,  depends  on  three  factors: 

1.  Water; 

2.  Gasoline; 

3.  Steam. 

The  water  carried  in  the  tank  must  be  delivered  in  proper 
quantities  to  the  generator,  where  it  is  flashed  into  steam. 

Gasoline  must  be  delivered  in  the  proper  quantities  to  the 
burner  so  that  the  correct  heat  is  maintained  to  generate  and 
superheat  the  steam. 

The  steam  must  be  supplied  in  a  highly  superheated  state,  in 
requisite  quantities  to  meet  the  varying  engine  demands. 

Since  a  generator,  or  flash  boiler  as  it  is  sometimes  called,  carries 
no  reserve  volume  of  water  or  steam,  the  intensity  of  the  fire  and  the 
quantity  of  feed  water  supplied,  must  be  continually  varied  to  cor- 
respond with  operative  conditions. 


544 


SHLF-PROPELLED  VEHICLES. 


STEAM  SYSTEMS.  545 

In  this  system,  i,  the  steam  pressure  is  made  to  control  the  sup- 
ply of  water  delivered  to  the  generator,  2,  the  water  pressure 
controls  the  gasoline  feed,  and  3,  the  steam  temperature  has  a 
bearing  on  the  water  supply.  Hence,  there  is  an  inseparable  inter- 
relationship among  the  gasoline,  water  and  steam. 

The  system  is  diagrammatically  illustrated  in  Fig-.  401.  In  the 
water  system,  the  water  must  go  from  the  water  tank  to  the 
generator;  it  is  drawn  from  the  tank  by  two  positively  driven 
pumps  P  on  the  engine  through  pipe  Pi.  From  each  pump  it  fol- 
lows the  piping  P2  to  the  flow  motor,  whose  workings  will  be 
considered  later ;  thence  to  the  feed  water  heater,  which  is  simply 
a  coil  of  pipe  at  the  engine  to  heat  the  water  before  it  goes 
through  pipe  ?3  to  the  generator. 

The  pumps  P  are  constantly  working  when  the  engine  is  run- 
ning, always  pumping  the  same  amount  of  water  per  minute,  at 
the  same  engine  speed;  however,  it  is  evident  that  sometimes 
more  steam  is  needed  than  at  others  at  the  same  engine  speed,  and 
consequently  more  water  will  be  needed. 

The  first  device  for  regulating  the  flow  of  water  is  the  water 
regulator  into  which  the  water  flows  by  pipe  P4.  Its  entrance 
to  the  regulator  is  governed  by  a  valve,  which  only  opens  when 
the  steam  pressure  gets  above  600  pounds. 

This  opening  is  accomplished  by  steam  pressure  through  the  pipe  83, 
acting  on  a  diaphragm  which  opens  the  valve,  letting  the  water  enter  the 
regulator  and  escape  through  the  pipe  PS  back  to  the  water  tank,  so  that 
when  there  is  600  pounds  pressure,  which  is  the  working  figure,  the  water 
delivered  by  the  pumps  P  does  not  [allow  the  course  to  pipe  P2  to  the 
generator,  but  is  by-passed  through  pipes  P4  and  PS  to  the  water  tank. 

With  the  water  delivered  to  the  generator,  gasoline  must  be 
delivered  also  in  order  to  have  heat  to  generate  steam.  The  gaso- 
line is  carried  under  pressure  in  the  tank  at  the  rear  of  the 
chassis,  and  starts  on  its  trip  to  the  burner  through  pipe  G,  the 
first  branch  Gi  goes  to  the  pilot  light  which  must  be  kept  burning 
all  the  time  the  car  is  running. 

This  pilot  light  is  a  small  flame  whose  heat  does  not  enter  into  chang- 
ing the  water  into  steam,  but  serves  solely  to  light  the  gasoline  vapor  in 
the  burner,  as  it  must  be  realized  the  burner  flame  is  out  one  minute  and 
on  the  next,  according  to  the  amount  of  steam  required;  the  automatics 
of  the  system  shut  off  and  turn  on  the  burner  according  to _  the  demand, 
but  the  pilot  light  always  burns  to  serve  as  the  match  for  ignition. 


546 


S8LP-PROPELLBD  VEHICLES. 


The  gasoline,  which  goes  to  generate  steam,  follows  pipe  G2, 
into  the  pointed  end  of  the  -flow  motor,  where  its  flow  is  regulated 
by  a  valve,  opened  and  closed  according  to  the  water  pressure, 
and  finally  reaches  the  burner  through  the  pipe  03.  Some  gaso- 
line controlling  valves  are  not  shown  in  the  diagram,  the  object 
of  this  diagram  being  merely  to  show  the  elements  of  the  system. 

Having  the  water  and  gasoline  at  the  generator,  steam  is  the 
product  and  its  course  to  the  engine  is  next  in  order.  It  follows 
the  main  pipe  S,  which,  before  reaching  the  engine,  has  an  en- 


-14 


FIG.  402. — The  White  water  regulator.  This  consists  of  a  diaphragm  valve 
operated  by  the  steam  pressure  in  the  generator. 

larged  section  Si  which  contains  the  copper  rod  of  the  ther- 
mostat, and  then  reaches  the  engine  through  the  continuation  pipe 
S2. 

There  is  a  branch  83  for  conveying  steam  pressure  to  the 
water  regulator. 

The  pyrometer  indicates  the  temperature  of  the  steam. 

In  brief,  the  action  of  the  thermostat  is  to  govern  an  additional 
supply  of  water  to  the  generator.  When  the  temperature  of  the 
steam  gets  too  high,  it  means  more  water  is  needed  in  the  gen- 


STEAM  SYSTEMS.  647 

erator,  and  the  thermostat  delivers  this  extra  water  supply  as  fol- 
lows: The  higher  temperature  of  the  steam  expands,  or 
lengthens  a  rod,  which  through  a  rocker  arm  opens  a  valve,  al- 
lowing water  from  the  main  supply  pipe  to  flow  through  the  pipe 
T  and  thence  through  pipe  Ti  into  the  How  motor, 

As  soon  as  the  temperature  of  the  steam  drops  to  normal,  the 
thermostat,  through  the  copper  rod,  automatically  shuts  off  this 
water  supply.  There  is  a  further  control  on  the  water  by  the 
flow  motor,  which,  at  a  certain  time,  by-passes  through  the  pipe 
W  water  to  the  tank. 

The  exact  operation  and  construction  of  the  water  regulator, 
the  thermostat,  and  the  flow  motor  follow. 

The  Water  Regulator. — This  device  is  shown  in  fig.  402,  and 
has  as  its  most  essential  feature  a  triple  diaphragm  D  against  one 
side  of  which  the  steam  from  the  engine  bears  through  the  pipe 
83.  On  the  other  side  of  the  diaphragm  is  a  metal  member  H, 
adjustably  secured  to  the  shaft  B,  and  which  member  at  its  op- 
posite end  bears  up  against  the  lever  L,  the  lower  end  of  which 
contacts  with  the  stem  of  the  valve  V.  This  valve  V  regulates 
the  water  entrance  ?4  from  the  pumps,  so  that  when  the  valve 
opens  water  enters  and  escapes  by  way  of  pipe  P5  to  the  water 
tank.  The  coil  spring  S  normally  holds  the  piece  H  against  the 
diaphragm  so  that  the  valve  V  closes.  However,  when  the  steam 
pressure  through  83  exceeds  a  certain  figure,  the  diaphragm  is 
forced  to  the  right  compressing  the  spring  S  and  opening  the 
valve  V,  allowing  the  water  to  flow  as  mentioned.  As  indicated 
in  fig.  401  the  water  is  by-passed  to  the  water  tank. 

The  Flow  Motor. — As  shown  in  fig.  403,  this  consists  of  three 
parts,  i,  the  right  section  W  in  which  the  water  control  is  ad- 
justed, 2,  the  small  end  portion  G  at  the  left  which  controls  the 
gasoline  flow  to  the  burner,  and  3,  the  connective  portion  C. 

Water  enters  direct  from  the  pumps  through  the  opening  WE 
passing  out  through  WD.  Its  control  of  the  water  is  by  the  piston 
P  which  when  moved  leftward  by  the  water  pressure  uncovers  the 
groove  G,  thus  allowing  the  water  to  pass  it  and  escape  through 
the  connection  WD.  This  piston  P  is  in  rigid  connection  with 
the  gasoline  controlling  valve  GV  in  the  left  compartment  of 


548 


SELF-PROPELLED   VEHICLES. 


the  flow  motor,  so 
that  the  valve  GV 
also  moves  leftward 
permitting  gasoline, 
which  enters  from  the 
gasoline  tank  through 
the  opening  Gl£  to 
escape  to  the  burner 
through  another  open- 
ing GD. 

The  faster  the  en- 
gine runs  the  greater 
the  volume  of  water 
delivered  by  the 
pumps  and  the  greater 
the  water  pressure 
against  the  piston  P 
the  further  will  it 
be  moved  leftward 
against  the  spring  S, 
the  more  water  will 
pass  it,  and  propor- 
tionately the  more 
gasoline  will  go  to  the 
burner. 

When  the  piston  P 
has  traveled  leftward 
a  certain  distance  it 
comes  in  contact  with 
the  end  H,  which  is 
on  the  stem  of  the 
valve  WV,  and  a 
further  leftward  move- 
ment of  the  piston  P 
opens  this  water  valve, 
which  allows  water  to 
escape  through  the 


STEAM  SYSTEMS. 


549 


by-pass  valve  WDi  and  thence  to  the  water  tank.  This  by-pass 
valve  opens  only  when  too  much  water  is  being  pumped,  and  lets 
a  portion  go  back  to  the  tank.  The  entrance  WEi  is  for  water 
admitted  from  the  thermostat  control. 

The  Thermostat. — This  device  is  a  regulator,  acted  on  by  the 
temperature  of  the  steam  after  it  leaves  the  generator,  but  before 
it  reaches  the  engine.  The  operation  of  the  thermostat  is  shown 
in  Fig.  404.  Steam  enters  through  SE  from  the  generator  and  de- 


^y  iriAM  rttoH  Goffwroi 

VW) 

JW*tt«.  TO  now  MOTOR.  , 

FIG.  404. — The  White  thermostat  for  regulating  the  temperature  of  the 
steam.  In  connection  with  the  thermostat,  is  a  pyrometer  in  which 
the  temperature  of  the  s+eam  is  shown  on  a  gauge. 

parts  through  opening  SD  to  the  engine.  In  its  passage  it  con- 
tacts with  a  copper  rod  T  anchored  rigidly  at  one  end  E  in  the 
casing,  and  at  the  end  El  bearing  upon  a  lever  L  which  bears 
upon  a  collar  on  the  valve  stem  VS.  The  high  temperature  of 
the  steam  lengthens  the  rod  T  which  through  the  lever  L,  opens 
the  valve  allowing  water  to  flow  to  the  flow  motor  and  thence 
to  the  generator,  thus  reducing  the  steam  temperature.  The  flow 
motor  lets  gasoline  go  to  the  burner  in  proportion  to  the  water 
sent  to  the  generator,  and  if  too  much  water  is  being  pumped,  it 
returns  a  portion  of  the  water  direct  to  the  water  tank. 


550 


SELF-PROPELLED   VEHICLES. 


To  Start  the  White  Car. — After  the  water  and  fuel  tanks  are 
filled,  air  pumped  to  30  pounds  by  the  hand  air  pump,  and  the 
generator  pumped  full  of  water,  the  sub-burner  V,  fig.  405,  is 
then  lighted. 

The  sub-burner,  will  in  about  five  minutes,  sufficiently  heat  the  vapor- 
izer N  to  vaporize  the  fuel  for  the  main  burner. 


FIG.  405. — Side  view  of  dash  of  White  car.  The  parts  shown  are  as  fol- 
lows: 42,  pyrometer;  43,  relief  cock  lever;  82,  cut  off  pedal  adjxist- 
ing  pin;  91,  cut  off  pedal;  93,  simpling  valve  pedal;  94,  air  pump 
valve  pedal;  95,  brake  pedal;  103,  emergency  gear  lever;  104,  reverse 
lever;  105,  brake  lever;  108,  cylinder  oiler  pump;  109,  crank  case 
oiler  pump;  111,  blow  off  valve;  112,  driving  shaft;  113,  emergency 
gear  rod;  120,  flow  motor;  209,  air  and  vaporizer  gauge;  210,  steam 
gauge;  D,  main  sub-burner  valve;  F,  sub-burner  adjusting  valve; 
G,  warming  up  valve:  HA.  pipe  connecting  valve  G  with  vaporizer 
N;  J,  main  burner  valve;  O,  vaporizer  nozzle;  V,  sub-burner  casing; 
W,  sub-burner  casing  door. 

To  start  the  main  burner,  the  warming  up  valve  G  is  slightly 
opened.  This  allows  the  fuel  to  flow  from  the  main  fuel  line 
into  the  vaporizer  N,  through  pipe  HA,  without  passing  through 
any  regulator.  Should  the  vaporizer  not  be  thoroughly  heated  a 


STEAM  SYSTEMS. 


551 


few  drops  of  raw  fuel  may  drip  from  the  vaporizer  nozzle  O. 
If  this  drop  be  continuous,  valve  G  should  be  closed  to  allow  the 
vaporizer  to  become  hotter. 

It  is  advisable  in  starting  to  open  and  close  valve  G  intermittently  four 
or  five  times,  the  interval  of  opening  being  about  two  seconds.  By  this 
means  any  sudden  rush  of  fuel  is  avoided  before  the  vaporizer  gets 
thoroughly  heated. 


FIG.  406. — The  "White  dash  as  seen  from  the  driver's  seat.  The  operat- 
ing devices  shown  in  the  cut  are  as  follows:  AA,  hand  air  pump; 
42,  pyrometer;  43,  relief  cock  lever;  82,  cut  off  pedal  adjusting  pin; 
91,  cut  off  pedal;  93,  simpling  valve  pedal;  94,  air  pump  valve  pedal; 
95,  brake  pedal:  108,  cylinder  oiler  pump;  109,  crank  case  oiler  pump; 
209,  air  and  vaporizer  pressure  gauge;  210,  steam  gauge.  The  small 
wheel  concentric  with  the  steering  wheel  is  the  throttle. 

\Yith  the  main  fire  satisfactorily  started,  valve  G  may  be  left 
open  about  one-quarter  turn.  The  safety  valve  should  now  be 
closely  watched.  This  is  important,  as  the  steam  pressure  runs 
up  very  quickly  and  any  inattention  when  the  fire  is  first  turned 


553  SELF-PROPELLED   VEHICLES. 

on  may  result  in  excessive  pressure  and  cause  the  safety  valve  to 
open.  As  soon  as  the  pressure  reaches  300  pounds,  the  surplus 
water  collected  in  the  pipe  should  be  blown  off  through  the  blow 
off  valve  in  fig.  405,  being  careful  to  close  this  valve  as  soon  as 
steam  appears.  The  steam  pressure  is  then  allowed  to  again 
reach  300  pounds.  The  warming  up  valve  G,  is  now  adjusted 
so  that  there  is  not  over  twenty  pounds  showing  on  the  vaporizer 
pressure  gauge  209. 

With  gear  lever  103  in  the  central  or  neutral  position,  so  that 
the  engine  may  run  without  moving  the  car,  and  with  cylinder 
relief  cocks  opened  by  lever  43,  the  engine  is  started  by  first 
pushing  the  starting  pedal  93  all  the  way  forward  and  then  open- 
ing slightly  the  throttle. 

The  water  should  be  worked  out  of  the  engine  easily  and  care- 
fully, by  cautious  handling  of  the  throttle  and  by  working  the 
reverse  lever  back  and  forth  from  forward  to  reverse  position 
until  the  engine  is  warmed  up  and  will  turn  over  freely.  Valve 
G  should  now  be  closed  and  valve  J  opened.  In  warming  up  the 
engine,  just  enough  steam  should  be  admitted  to  the  cylinders  to 
keep  the  engine  moving  slowly  until  all  the  water  is  out  when  it 
will  run  smoothly.  Until  all  the  water  is  out,  the  engine  will  run 
jerkily  on  account  of  this  water  filling  the  clearance  spaces  in 
passing  the  dead  centres,  hence,  the  engine  should  not  be  forced 
by  too  much  throttle  opening,  but  Ihe  water  should  be  worked 
out  gradually. 

When  engine  runs  smoothly,  the  relief  cocks  may  be  closed  by 
throwing  lever  43  over  to  the  right  hand  position.  To  get  the 
cylinders  thoroughly  heated,  the  foot  is  transferred  from  the 
starting  pedal  to  the  cut  off  pedal  91  and  the  latter  pressed  for- 
ward so  that  steam  will  be  admitted  for  full  stroke.  The  engine 
should  be  run  thus  for  about  one-half  minute  and  then  for  two 
or  three  minutes  with  cut  off  pedal  in  its  normal  position,  allow- 
ing the  steam  to  work  expansively. 

The  air  presure  is  now  pumped  to  50  pounds,  and  the  sub- 
burner  adjusted  to  this  pressure  after  which  the  car  may  be 
started. 


STEAM  SYSTEMS.  553 

Summary. — The  operation  of  the  White  system  may  be  stated 
briefly  as  follows : 

1.  When  the  engine   is   running,   it  operates  the   feed  water 
pumps. 

2.  The  water  regulator  either  by-passes  back  to  the  tank  all  of 
the  water  delivered  by  the  pumps,   when  the   steam  pressure 
exceeds  550  pounds,  or  it  allows  all  of  the  water  to  flow  toward 
the  generator  when  the  steam  pressure  is  less  than  550  pounds. 

That  is  to  say,  the  water  supply  is  controlled  by  an  "all  on"  or  "all  off" 
action — the  required  variations  being  due  to  changes,  automatically 
brought  about  in  the  frequency  and  durations  of  these  "all  on"  periods. 

3.  The  feed  water  from  the  pumps  flows  through  two  branches : 

a.  The  flow  motor  branch ; 

b.  The  thermostat  branch. 

The  water  going  through  the  flow  motor  branch  moves  a  piston  in 
the  flow  motor  which  in  turn,  proportionately  opens  the  fuel  valve.  It 
also  opens  the  by-pass  valve  in  the  flow  motor,  when  the  rate  of  water 
flow  into  the  flow  motor  exceeds  the  capacity  of  the  generator,  and  by- 
passes the  excess  water. 

The  water  going  through  the  thermostat  branch,  is  increased  or  de- 
creased in  amount  by  the  action  of  the  thermostat  in  opening  or  closing 
the  water  valve  of  the  thermostat.  This  action  produces  the  necessary 
variations  in  the  ratio  between  the  fuel  supply  to  the  burner  and  feed 
water  supply  to  the  generator. 

The  practical  result  of  the  automatic  actions  of  the  different 
members  of  the  system  is  to  maintain  the  steam  at  a  practically 
uniform  high  pressure  with  a  considerable  degree  of  superheat 
under  all  working  conditions. 

Flash  Steam  Data. — The  following  results  were  obtained  in 
a  series  of  tests  made  on  the  steam  plant  of  the  White  steamer. 
For  the  purpose  of  testing,  the  engine  was  mounted  on  the 
frame  of  a  car  in  the  same  manner  as  in  the  completed  motor 
car,  which  was,  however,  supported  by  solid  posts  instead  of 
by  wheels.  The  main  shaft  of  the  engine  was  connected  to  an 
Alden  Prony  brake  and  all  the  horse  power  calculations  were 
for  brake  horse  power,  it  being  deemed  not  advisable  to  use  the 
indicator  on  account  of  the  small  size  and  high  speed  of  the  en- 
gine. 


554 


SELF-PROPELLED    VEHICLES. 


During  certain  of  the  various  tests  the  boiler  pressure  averaged  595 
pounds,  the  steam  chest  pressure  varied  with  the  load  from  152  pounds  to 
427  pounds,  averaging  303  pounds.  The  temperature  of  the  steam  near 
the  boiler  average  783°  Fahr.,  and  that  in  the  steam  chest  757°.  This 
indicates  that  the  steam  leaving  the  boiler  was  superheated  nearly  300°,  that 
entering  the  steam  chest  about  340°,  and  that  exhausted  about  28°,  so  that 
the  steam  in  its  entire  passage  through  the  engine  remained  in  a  super- 
heated condition. 

The  actual  evaporation  from  feed  water  at  78°  to  steam  with  the  pres- 
sure and  temperature  as  shown  averaged  10.34  pounds  of  water  per 
pound  of  gasoline.  The  equivalent  evaporation  "from  and  at  212°"  per 
square  foot  of  heating  surface  per  hour  was  13  pounds  for  the  highest  re- 
sult. 

The  engine  developed  a  horse  power  on  the  brake  at  its  highest  load 
with  a  consumption  of  11.96  pounds  of  feed  water  per  hour.  This  re- 
markably small  consumption  of  feed  water  shows  the  value  of  super- 
heating the  steam,  it  being  well  known  in  steam  engineering  that  the 
saving  in  feed  water  due  to  superheating  is  a  little  over  one  per  cent,  for 
each  10°  of  superheat. 

The  important  facts  brought  out  by  the  tests  are :  i,  the  feed  water  con- 
sumption of  a  small  compound  non-condensing  engine  using  highly  super- 
heated steam  is  very  small;  2,  when  a  flash  boiler  is  used,  the  required 
amount  of  heating  surface  to  run  the  engine  is  approximately  one  square 
foot  per  brake  horse  power. 

The  following  table  shows  the  results  of  some  of  Prof.  Carpenter's 
tests : 


Total  Lbs. 

B.  T.  U.  Above  212° 

1 

O 
JO      • 

to  Engine. 

& 

0)   g 

m 

.9 

1 

y 

A 

5 

13 

Per  Lb.  of  Steam. 

0) 

a 

c"S  5 

^ 

M 

te 

M 

£* 

.,    i_, 

23 

.2  a 

.2  M    O 

b 

• 
P. 

1 

O 

PM 

b 

B 

o 

m 

Is 

£« 

E 

c3 

Q, 

I! 

o§ 

I-? 

3 

1 

p 

1 

n 

• 
s 

W    M 

PH 

1. 

^ll 

|o 

OS'S  °* 
>   0  0 

H 

s 

w 

A 

o 

p,  u 

1 

«-g 

t>  «iS 

K  d 

W&H    oj 

•3 

3 
0 

« 

Ji 

1 

» 

!_    0> 
-    ' 

a 

*!;£ 

i 

.E 

id 

1*1 

> 

•w 

• 

• 

£ 

6 

to 

0 

B 

3 

O 

o 

M 

fc 

W 

^ 

O 

" 

O! 

EH 

« 

^ 

^M 

14 

850 

72 

25.50 

320.0 

31.125 

12.55 

1034 

198 

1232 

257 

10.30 

6.98 

15 

850 

85 

30.1 

370.031.125 

12.29 

1036 

196 

1234 

252 

10.42 

8.07 

15a 

850 

85 

30.1 

370.035.5 

12.29 

1038 

196 

1234 

252 

10.42 

8.07 

15b 

850 

85 

30  1 

371.535.5 

12.30 

1035 

202 

1237 

253 

10.45 

8.11 

16 

850 

96 

34.0 

408.839.25 

12.05 

1036 

200 

1236 

246 

10.40 

8.87 

17 

850 

115 

40.7 

488.048.0 

11.96 

1037 

197 

1224 

244 

10.15 

10.7 

av.  = 

1228 

av. 

10.34 

CHAPTER  FORTY. 

ELECTRIC   VEHICLES. 

The  Term  Electric  Vehicle. — This  is  broadly  applicable  to  al 
great  variety  of  either  passenger  or  freight  carrying  machines 
which  are  propelled  by  electric  energy  supplied  from  either 
storage  batteries  or  electric  generators  installed  on  the  machines 
themselves,  but  does  not  include  the  storage  cars  used  for  electric 
traction  or  railway  purposes. 

The  principal  types  of  electric  vehicles  which  are  commercially 
successful  at  the  present  time  are : 

1.  Electric  automobiles,  represented  by  various  types  of  road- 
sters, coupes,  phaetons,  cabs,  etc.,  suitable  for  the  use  of  physi- 
cians, business  men  and  others,  in  city  service. 

2.  Heavy  electric  trucks  and  vans  for  moving  merchandise,  and 
for  delivering  purposes. 

3.  Gasoline-electric  trucks,  which  represent  an  attempt  to  over- 
come the  lack  of  flexibility  of  internal  combustion  engine  by 
combining  it  with  a  direct  current  generator  and  storage  battery. 

The  Motors. — For  electric  vehicles  these  are,  in  all  respects, 
quite  similar  to  railway  motors,  except  that  they  are  designed 
to  operate  safely  at  severaJ  hundred  per  cent,  overload,  whenever 
necessary,  as  for  instance,  when  propelling  the  vehicles  up  a 
steep  hill  or  incline  or  over  a  heavy  road,  so  that  in  spite  of  their 
low  power  rating,  they  yield  a  high  percentage  of  efficiency  and 
are  capable  of  operating  under  several  different  pressures,  and  a 
corresponding  number  of  different  speeds. 

The  accepted  forms  of  the  mechanical  part  of  the  transmission 
or  drive  are  of  the  herringbone  gear  and  the  double  reduction 
types,  while  the  direct  connected  spur  gear  has  fallen  into  general 
disuse. 

555 


556 


SELF-PROPELLED  VEHICLES. 


The  motor  is  usually  hung  above  the  springs,  thus  being  pro- 
tected from  the  jars  of  travel.  There  are,  however,  several 
forms  of  double  reduction  using  high  speed,  light  motors  by 
means  of  various  combinations  of  gear  and  chain,  with  silent  or 
roller  chains  or  herringbone  gears  for  the  first  reduction,  and 
single  or  double  roller  chains,  level  gears  or  herringbone  gears 
for  the  second  reduction. 

Light  Electric  Vehicles. — These  are  of  various  types,  such  as 
roadsters,  Victorias,  phaetons,  runabouts  and  coupes,  and  are 
equipped  with  batteries  which  have  a  capacity  ranging  from  75  to 


Fi0.407«-Heayy  truck  of  the  Vehicle  Equipment  Co.     Carrying  capacity,  4  tons; 
speed,  6  miles  per  hour ;  travel  radius  on  one  charge  of  battery,  25  miles. 

TOO  miles  per  charge,  with  controller  arrangements  for  providing 
speeds  varying  from  6  to  26  miles  per  hour.  In  these  cases  the 
number  of  cells  in  each  battery  may  vary  from  10  to  30  according 
to  the  make  and  number  of  plates  in  each  cell.  The  number  of 
pates  in  each  cell  may  vary  from  n  to  21. 

Electric  Trucks  for  City  Service. — Under  certain  traffic  con- 
ditions and  surface  requirements,  the  superior  mobility  of  the 
gasoline  engine  truck  effects  a  saving  in  drivers  sufficient  to  com- 
pensate for  the  higher  maintenance  charges,  but  when  the  num- 


ELECTRIC   VEHICLES. 


557 


ber  of  active  trucks  are  the  same  in  each  case,  the  electric  truck 
becomes  more  economical  on  account  of  its  lower  maintenace 
charge. 

The  gasoline  engine  truck  has  the  advantage  in  all  classes  of  service 
requiring  a  greater  mileage  than  that  which  is  conveniently  obtainable 
with  the  electric  truck,  but  the  greater  portion  of  city  delivery  service  is 
well  within  the  limits  of  the  safe  operative  mileage  radius  of  the  electric 
trucks  built  at  the  present  time. 


Gasoline-Electric  Vehicles.— The  principal  disadvantage  of 
the  internal  combustion  motor  or  self-propelled  vehicles  is  its  lack 
of  flexibility ;  while  on  the  other  hand,  the  principal  disadvantage 
of  the  electric  vehicle  operated  by  means  of  storage  batteries  is 
its  lack  of  mobility.  It  is  evident  that  the  short  coming  in  each 
case  can  be  overcome  only  by  combining  the  internal  combustion 
motor  with  a  direct  current  generator  connected  to  a  storage  bat- 
tery, for  supplying  the  power  required  by  the  electric  motors. 

Such  a  combination  will  operate  jit  practically  constant  speed 


558 


SELF-PROPELLED   VEHICLES. 


at  all  loads,  as  the  generator  with  the  storage  battery  serves  to 
furnish  the  necessary  overload,  or  consumes  that  portion  of  the 
energy  which  is  not  needed.  Furthermore,  the  transmission  will 
be  entirely  electrical  and  will  possess  the  simplicity  and  flexibility 


of  electric  control ;  while  the  use  of  motors  will  eliminate  all  dif- 
ferential gears  and  allow  the  attainment  of  various  speeds  by 
series-parallel  combinations. 

A  great  many  vehicles  of  this  type  are  now  being  built  in  the  form  of 
omnibuses  and  trucks  for  city  service  and  freight  and  passenger  cars  for 
interurban  railway  service  in  which  they  have  rendered  satisfactory  duty. 


CHAPTER  FORTY-ONE. 

PRINCIPLES  OF  ELECTRICITY. 

The  Term  Electricity. — This  is  derived  from  the  Greek  word 
electrom — amber.  It  was  discovered  more  than  2,000  years  ago 
that  amber  when  rubbed  with  an  ox's  tail  possessed  the  curious 
property  of  attracting  light  bodies.  It  was  discovered  afterwards 
that  this  property  could  be  produced  in  a  dry  steam  jet  by  friction, 
and  in  A.  D.  1600  or  thereabouts,  that  glass,  sealing  wax,  etc., 
were  also  affected  by  rubbing,  producing  electricity. 

For  convenience,  electricity  is  sometimes  classified  as: 

1.  Static  electricity,  or  electricity  at  rest. 

2.  Dynamic  electricity,  or  electricity  in  motion. 

3.  Magnetism,  or  electricity  in  rotation. 

Static  Electricity  is  a  term  employed  to  define  electricity 
produced  by  friction.  It  is  properly  employed  in  the  sense  of  an 
electric  charge  which  shows  itself  by  the  attraction  or  repulsion 
between  charged  bodies. 

When  static  electricity  is  discharged,  it  causes  more  or  less  of  a  cur- 
rent, which  shows  itself  by  the  passage  of  sparks  or  a  brush  discharge ;  by 
a  peculiar  prickling  sensation ;  by  an  unusual  smell  due  to  its  chemical 
effects ;  by  heating  the  air  or  other  substances  in  its  path ;  and  sometimes 
in  other  ways. 

Dynamic  Electricity. — A  classification  used  to  define  cur- 
rent electricity  to  distinguish  it  from  static  electricity.  The  term 
positive  expresses  the  condition  of  the  point  having  the  higher 
electric  energy  or  pressure,  and,  negative,  the  lower  relative  con- 
dition of  the  other  point,  and  the  current  is  forced  through  the 
circuit  by  the  electric  pressure  at  the  source,  just  as  a  current  of 
steam  is  impelled  through  pipes  by  the  generating  pressure  at  the 
steam  boiler. 

559 


560 


SELF-PROPELLED   VEHICLES. 


Units  of  Electrical  Measurement. — These  are  stated  in  terms 
of  length,  weight  and  time,  which  is  to  say  in  terms  of  centi- 
meters, grams  and  seconds.  The  units  thus  established  are 
largely  arbitrary,  but  they  have  been  carefully  estimated,  so  that 
the  proportions  between  current  strength,  circuit  resistance  and 
voltage  may  be  accurately  maintained. 

The  Ohm,  the  Unit  of  Resistance. — The  first  unit  of  electri- 
cal measurement  is  the  ohm.  This  unit  measures  not  only  the 
relative  resistance  of  a  circuit  composed  of  a  conducting  wire  of 
a  given  length  and  diameter,  as  compared  with  wires  of  different 


Fia. 4 10.— Diagram  Illustrating  the  Action  of  Voltaic  Induction  Between  Two  Circuits: 
the  one  including  a  source  of  electrical  energy  and  a  switch;  the  other  including  a 

falvanometer,  but  having  no  cell  or  other  electrical  source.    The  direction  of  the 
attery  current  in  circuit  1  is  indicated  by  the  arrow;  the  arrow  in  circuit  2  showing 
the  direction  of  the  induced  current. 

lengths  and  diameters,  composed  of  the  same  material,  but  also 
the  specific  resistance,  which  refers  to  the  variations  in  resisting 
quality  found  between  given  wires  of  the  same  length  and  cross- 
section,  made  of  different  materials. 

The  different  resistivity  of  several  different  metals,  as  found  in  cir- 
cuits, precisely  similar  in  all  points  of  dimensions,  is  demonstrated  in  the 
fact  that,  while  a  unit  wire  of  silver  shows  a  conductivity  of  100,  and  one 
of  copper,  99,  a  wire  of  iron  gives  oniy  16.80. 


PRINCIPLES  OF  ELECTRICITY.  561 

The  value  of  the  ohm,  as  fixed  by  the  Electrical  Congress,  at  the  Co- 
lumbian Exposition  in  1893,  is  equivalent  to  the  resistance  offered  to  one 
volt  of  E.  M.  F.  by  a  column  of  mercury  106.3  centimeters  in  height 
(about  41.3  inches),  and  one  square  millimeter  (.00155  square  inch)  cross- 
section,  determined  at  the  temperature  of  melting  ice  (39°  Fahrenheit). 

The  Ampere,  the  Unit  of  Current. — The  ampere  is  the  cur- 
rent produced  by  an  electromotive  force  of  one  volt  in  a  .circuit 
having  a  resistance  of  one  ohm.  An  ampere  is  that  quantity  of 
electricity  which  will  deposit  .005084  grain  of  copper  per  second. 

It  is  one-tenth  the  absolute  C.  G.  S.  unit  of  current  strength.  Current 
in  amperes  equals  pressure  in  volts  divided  by  resistance  in  ohms,  or 
again,  electromotive  force  equals  resistance  multiplied  by  current ;  and 
again,  resistance  equals  electromotive  force  divided  by  the  current;  thus, 
it  will  be  seen  that  these  terms  are  dependent  upon  each  other,  and  that 
their  relation  to  each  other  is  expressed  by  this  law.  These  are  written 
in  three  ways : 

i.  c.-5 

2.  E.  -  C  x  R,  or 

3.  R.-§ 

If  one  volt  will  force  one  ampere  of  current  through  a  circuit  having 
one  ohm  resistance  it  will  take  five  volts  to  force  five  amperes  through  the 
same  circuit.  If  this  resistance  should  be  increased  to  five  ohms  it  would 
take  five  times  five  volts  for  the  proper  number  of  volts  to  force  the 
amperes  through,  which  would  be  25  \olts.  From  this  it  can  be  seen  that 
it  is  very  easy  to  obtain  any  one  of  these  quantities  when  we  have  the 
other  two. 

The  Volt,  the  Unit  of  Pressure. — The  volt  is  that  electro- 
motive force  which  can  produce  a  current  of  one  ampere  on  a 
circuit  having  a  resistance  of  one  ohm. 

There  are  several  specified  equivalents  for  estimating  the  -exact  value 
of  one  volt  E.  M.  F.,  but  these  usually  refer  to  the  determined  capacity  of 
some  given  type  of  galvanic  cell. 

It  is  sufficient  to  say,  however,  for  ordinary  purposes,  the  majority  of 
commercial  chemical  cells  are  constructed  to  yield  approximately  one 
volt. 

The  ordinary  Daniell  cell  used  in  telegraphy  has  a  capacity  of  1.08  volt, 
and  the  common  type  of  Leclanche  cell  gives  about  1.50. 

The  Watt,  the  Unit  of  Work. — This  represents  the  rate  of 
energy  of  one  ampere  of  current  under  a  pressure  of  one  volt, 
and  is  equivalent  to  the  product  of  the  voltage  multiplied  by  the 
amperage. 


562 


SELF-PROPELLED  VEHICLES. 


Other  equivalents  of  the  watt  make  it  equal  to  the  product  of 
the  resistance  by  the  square  of  the  current,  or  the  quotient  of 
the  square  of  the  voltage  by  the  resistance. 

Thus,  a  current  of  ten  amperes  at  a  pressure  of  2,000  volts  will  develop 
20,000  watts,  as  will  also  another  given  current  of  400  amperes  at  fifty  volts. 

Electrical  Horse  Power. — The  operative  capacity  of  an  elec- 
trical motor  is  usually  stated  in  terms  of  watts,  or  kilowatts  ( 1,000 
watts),  which  may  be  reduced  to  horse-power  equivalents  by  di- 
viding by  746,  which  figure  indicates  the  number  of  watts  to  an 
electrical  horse  power. 


FlO.411. 


Fio. 412. 


FIGS.  411.  and  41 2<— Sectional  Diagrams  Illustrating  the  Construction  of  Volt 
and  Ammeters.  The  iron  core  is  secured  to  the  base  plate  by  a  screw. 
The  active  coil  is  shown  wound  around  it  from  end  to  end. 

The  Energy  Consumption  of  Electric  Vehicles. — The  cur- 
rent consumption  of  electric  vehicles  operated  by  storage  batteries 
varies  more  or  less  with  the  different  makes,  but  some  idea  of 
the  same  may  be  obtained  from  the  results  of  a  test  run  of  62 
miles  over  dirty  and  slippery  roads  recently  made  in  France. 


PRINCIPLES  OF  ELECTRICITY. 


563 


In  this  run,  a  number  of  electric  vehicles,  each  carrying  four  passengers 
and  weighing,  complete,  over  2  tons,  covered  the  entire  distance  at  an 
average  speed  of  15  miles  an  hour,  with  an  energy  consumption  of  about 
160  watt-hours  per  ton  mile. 

The  best  performance  was  that  of  a  Vedrine,  which  required  155  watt- 
hours  per  ton  mile.  Under  ordinary  conditions  this  vehicle  consumes 
from  no  to  120  watt-hours  per  ton  mile. 

Electricity  Meters. — The  electrical  gauges,  ammeters  and 
voltmeters,  used  on  automobiles  are  constructed  on  the  principle 
of  the  D'Arsonval  galvanometer,  with  either  a  permanent  or  a 
variable  field. 


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'10 


PIG.  413.— Index  Scales  of  a  Voltmeter  and  an  Ammeter  for  Measuring  /-toe 
Pressure  and  Intensity  on  a  Direct-current  Electrical  Circuit. 

The  general  features  are  a  small  oscillating  solenoid  whose  core  is 
mounted  on  jeweled  bearings,  arranged  like  a  dynamo  armature  between 
the  poles  of  the  permanent  horseshoe  magnet,  with  a  hand  or  pointer 
pivoted  at  the  bearing,  so  as  to  indicate  the  variation  in  electrical  condi- 
tions on  a  graduated  scale. 

A  coiled  steel  spring  attached  at  the  base  of  the  needle  acts  to  restrain 
and  control  its  movements,  thus  ensuing  reliable  indications  of  current 
strength  or  intensity. 

Forms  of  VoIt=Ammeter. — For  automobile  use  a  voltmeter 
and  an  ammeter  are  usually  mounted  on  one  base,  with  their 
graduated  scale  cards  sufficiently  near  together  to  enable  rapid 
reading  of  battery  conditions.  These  instruments  frequently  have 
the  scale  traced  on  glass,  so  as  to  be  illuminated  at  night  by  an 
incandescent  lamp  placed  behind  it. 


564  SELF-PROPELLED   VEHICLES. 

As  shown  in  figs.  413  and  414,  volt-ammeters  made  by  different 
manufacturers  vary  in  appearance — one  type  having  the  two 
scales  arranged  side  by  side,  another  end  to  end.  The  voltmeter 
indicates  the  pressure  between  battery  terminals,  while  the  am- 
meter scale  indicates  the  current  strength. 

Reading  Speed  and  Power  Output. — In  running  the  vehicle 
the  voltmeter  scale  reading  indicates  the  amount  of  charge  still 
remaining  in  the  battery — the  difference  between — and  the  am- 
meter rate  at  which  it  is  being  used. 

If  the  speed  of  a  vehicle  on  a  hard  level  road  be  determined  and  the 
reading  noted  in  connection  with  it,  the  ammeter  may  be  used  as  a  very 
good  speed  indicator  for  operation  under  similar  conditions. 

The  ammeter  indicates  an  overload,  which,  if  above  a  definite 
specified  figure,  would  likely  damage  the  battery,  as  when  at> 
tempting  to  start  with  brakes  set,  or  in  beginning  the  ascent  of  a 
heavy  grade  from  a  standstill.  The  amount  of  power  being  con- 
sumed by  the  motor  is,  of  course,  always  the  product  of  the  volts 
by  the  amperes.  Thus,  with  readings  of  80  volts  and  16  amperes, 
1,280,  or  about  1.7  horse  power,  are  being  constantly  used. 

Voltmeter  Indications. — Although  the  voltmeter  should 
always  register  between  1.75  and  2.6  per  cell,  the  former  figure 
indicating  the  point  of  discharge — it  may  happen'  that  an  un- 
usually heavy  road  will  bring  the  needle  temporarily  below  that 
point.  Such  indication  does  not  of  necessity  mean  that  the  bat- 
tery is  exhausted,  as  on  coming  upon  a  better  road,  it  will  quickly 
resume  its  normal  reading. 


CHAPTER    FORTY-TWO. 

TH£  OPERATION  AND  CONSTRUCTION  OF  DYNAMOS  AND  MOTORS. 

Dynamos  and  Motors. — The  machines  for  converting  me- 
chanical movement  into  electrical  current,  and  for  conveying  elec- 
trical current  into  mechanical  movement,  in  other  words,  the 
dynamo  generator  and  the  electric  motor,-  respectively,  are  the 
same  so  far  as  the  general  features  of  their  construction  are  con- 
cerned. In  operation,  however,  the  motor  is  the  exact  reverse  of 
the  dynamo. 


PIG.  414.— Weston  Volt-ammeter  of  the  Type  used  on  Electric  Vehicles. 
Other  makes  of  these  instruments  have  the  index  scales  side  by  side, 
instead  of  end  to  end. 


The  Essential  Parts  of  Dynamos  and  Motors. — The  essen- 
tial parts  of  a  dynamo  generator  and  also  of  an  electric  motor 
are: 

i.  The  field  mag-nets  constructed  like  ordinary  electromagnets, 
and  having  two  or  any  even  number  of  opposed  poles  with  their 
windings  connected  in  series. 

605 


566 


SELF-PROPELLED   VEHICLES. 


2.  The  armature  rotating-  between  the  fields,  so  as  to  cut  the 
lines  of  magnetic  force. 

3.  The  pole  pieces,  which  are  the  exposed  ends  of  the  magnet 
cores. 


FIG.  415.— Diagram  Illustrating  the  Directions  of  the  Current  in  the  Field 
"Windings  and  the  Induced  Current,  as  found  in  magnets,  solenoids  and 
dynamo  operation. 


3fta.  416,-Diagram  of  a  Dynamo  Electrical  Generator,  arranged  for  producing  an  alter- 
nating current,  showing  the  constructional  and  operative  features.  Here  N  and  S 
are  the  positive  and  negative  poles  of  the  field  magnets,  between  which  the  lines  of 
force  are  shown  by  the  dotted  lines.  A  is  the  armature  spindle;  B1  and  B3,  the 
brushes  bearing  on  the  ring  drums;  C,  the  coil,  or  winding,  of  the  armature;  E,  the 
outside  circuit  to  which  the  current  is  supplied. 

4.  The  commutator  or  collector. 

5.  The  brushes  which  rest  upon  the  cylindrical  surfaces  of  the 
commutator,  and  as  the  terminals  of  the  outside  circuit,  take  up 
and  deliver  the  current  generated  in  the  coils  of  the  armature. 


DYNAMOS  AND  MOTORS.  567 

The  Varieties  of  Dynamo-Generators. — There  are  a  number 
of  species  of  dynamo,  differing  in  details,  such  as  the  arrange- 
ment of  the  armatures,  the  winding  of  the  field  magnets,  etc.,  ac- 
cording to  the  use  for  which  they  are  intended. 

Series  Motor. — The  motors  used  on  electric  carriages  are 
generally  series  wound,  that  type  having  been  found  very  well 
adapted  to  most  ordinary  requirements,  and  from  many  points  of 
view  the  most  efficient  in  operation.  It  also  possesses  the  valu- 
able characteristic  of  automatically  adjusting  the  consumption  of 
power,  as  it  were,  to  the  load. 


Fio.  417.— A  Typical  Dynamo-Electrical  Generator,  with  parts  lettered.  A,  the  armature; 
B,  B,  the  brushes;  C,  the  commutator;  E,  E,  the  windings  of  the  field  magnets;  M, 
the  pole  piece  of  the  salient  field  magnet;  F,  F,  bearings  of  the  armature  spindle; 
L,  L,  the  lead  wires;  P,  the  pulley;  T,  T,  terminal  connections  of  the  outside  circuit. 

Thus,  at  a  light  load  it  will  take  small  current,  while  as  the  resisting 
torque  on  the  machine  increases,  power  sufficient  for  demands  is  con- 
stantly absorbed,  thus  enabling  the  motor  to  take  extreme  overloads  with 
high  efficiency. 

Shunt  and  Compound  Motors. — With  a  view  to  increasing 
the  efficiency  or  automobile  motors,  several  designers  have  pro- 
posed the  use  of  shunt  and  compound  windings,  whose  advantages 
in  several  particulars  have  been  made  apparent  in  other  branches 
of  electrical  activity. 


568 


SELF-PROPELLED  VEHICLES. 


Shunt  wound  motors,  in  which  the  field  coils,  instead  of  being 
in  series  with  the  armature,  are  on  a  shunt  between  the  lead 
terminals,  are  very  largely  used  on  constant-potential  circuits, 
on  account  of  their  ability  to  regulate  the  speed,  maintaining  it 
at  a  virtually  uniform  rate,  in  spite  of  the  increase  in  load  up  to  a 
certain  point. 

In  hill  climbing,  one-third  and  even  more  of  the  extra  energy  con- 
sumed can  be  recovered  by  coasting  down  the  other  side  with  the  con- 
troller set  a  notch  or  two  below  the  coasting  speed. 


FIG.  4 1 8. -Plan  Diagram  of  Single  Motor  Attached  to  Rear  Axle  Through 
"Herring-bone"  Single  Reducing  Gears.  A  is  the  left-hand  section  of 
the  divided  rear  axle;  B,  the  right-hand  section  of  the  rear  axle;  C,  the 
brake  drum;  D,  the  spiral  pinion  on  the  motor  shaft  driving  the  worm 
gear,  I,  on  the  differential;  E,  plug  for  greasing  gears;  F,  set  screw  for 
locking  ball  race;  G,  slot  for  wrench  to  adjust  threaded  ring,  H,  against 
ball  bearings. 

The  Commutator  and  Its  Use. — In  general,  the  commutator  is 
formed  of  alternating  sections  of  conducting  and  non-conducting 
material,  running  lengthwise  to  the  axis,  upon  which  it  turns. 
The  commutator  is  used  to  collect  the  current  produced  by  the 
cutting  of  the  lines  of  magnetic  force,  so  as  to  cause  them  all  to 
concur  to  a  desired  result,  transforming  what  would  naturally  be 
an  alternating  current  into  a  direct  current. 

Electric  Motor  Troubles. — The  following  digest  of  common 
motor  troubles  is  given  by  Mr.  George  T.  Hauchett  in  The  Auto- 
mobile, and  is  re-printed  by  permission: 


DYNAMOS  ~AND   MOTORS.  569 

"While  it  is  not  necessary  to  be  an  electrician  to  operate  an  elec- 
trically driven  vehicle,  it  is  of  great  advantage  to  know  what  to 
do  when  certain  troubles  occur. 

"Let  us  consider  first  a  single  motor  equipment  provided  with 
a  battery  which  is  connected  in  different  ways  for  the  various 
speeds.  Suppose  an  attempt  is  made  to  start,  and  the  vehicle 
does  not  respond  and  the  ammeter  shows  no  indication.  This 
almost  invariably  means  open  circuit ;  that  is  to  say,  the  path  for 
the  electricity  from  the  batteries  to  the  motors  is  not  closed.  We 
may  find  open  circuits  at  any  of  the  following  points : 

"A.  The  battery  contacts.  They  may  be  and  often  are  so  badly 
corroded  as  to  prevent  the  necessary  metal-to-metal  contact. 

"B.  The  controller.  A  connection  may  be  loose  or  the  fingers 
may  not  make  contact. 


FIG.  419.  Fio.  420. 

FIG.  419.— General  Electric  Slemens-Halske  Type  of  Vehicle  Motor.  Four- 
pole,  cylindrical,  laminated  fields.  Capacity,  16  amperes  at  80  volts;  1,000 
R.  P.  M.  under  full  load. 

FIG.  420.— General  Electric  Motor  for  Medium-weight  Vehicles.  Capacity, 
16  amperes  at  85  volts;  850  R.  P.  M.  at  full  load. 

"C.  The  running  plug  may  sometimes  be  out  or  not  making 
proper  contact. 

"D.  The  motor  brushes.  May  have  dropped  out  or  the  tension 
may  be  so  weak  that  they  do  not  make  contact. 

"E.  The  emergency  switch  may  be  open. 

"Leave  the  controller  till  the  last  It  is  but  a  moment  to  in- 
spect the  other  joints  and  to  discover  the  trouble  in  them  after 
an  hour's  fussing  with  the  controller  is  clearly  a  waste  of  time. 

"If  the  motor  tries  to  start,  but  the  current  is  not  sufficient,  as 
shown  by  the  ammeter,  poor  contact  or  weak  battery  may  be  sus- 
pected. Discharged  battery  will  be  betrayed  by  a  low  voltmeter 


570  SELF-PROPELLED   VEHICLES. 

indication,  but  if  the  voltmeter  registers  the  normal  amount, 
poor  contact  should  be  sought.  Any  contacts  which  are  part  of 
the  electric  circuit,  such  as  binding  posts,  brushes,  switch  jaws 
or  controller  fingers  must  be  bright  metal-to-metal  contacts.  If 
they  are  dirty  or  corroded  the  contact  may  be  so  bad  that  the  flow 
of  current  is  seriously  reduced  or  interrupted  altogether. 

"Improper  Connections. — Sometimes  the  absence  of  ampere 
indication  and  no  motion  of  the  vehicle  points  to  a  very  serious 
trouble,  namely,  the  improper  connection,  of  the  batteries.  This 
will  be  shown  by  heavy  sparks  at  the  controller;  in  fact,  heavy 
sparks  at  the  controller,  absence  of  ammeter  indications  and  re- 
fusal of  the  vehicle  to  move,  could  only  be  caused  by  one  other 
difficulty  than  this,  which  will  be  discussed  further  on. 

"When  the  battery  is  not  properly  connected,  the  motion  of 
the  controller  causes  the  sections  of  battery  to  exchange  current 
between  themselves  at  a  ruinous  rate.  The  terminals  of  the  cells 
and  those  to  which  they  should  be  connected  ought  to  be  plainly 
marked,  or,  better  still,  so  constructed  that  it  is  impossible  to 
go  wrong.  If  the  trouble  just  cited  is  the  fact,  one  or  more  sets 
of  terminals  of  the  cells  will  be  found  to  be  connected  to  the 
wrong  wires. 

"If  the  vehicle  fails  to  move  and  the  flow  of  current  as  indi- 
cated by  the  ammeter  is  enormous,  shut  off  the  power  at  once. 
Serious  damage  may  ensue  if  this  is  not  done.  Then  look  to  see 
if: 

"A.  The  brakes  are  on. 

"B.  The  vehicle  is  stalled  or  blocked. 

"C.  The  gears  are  free  and  there  is  no  obstacle  between  the 
teeth. 

"If  the  motor  makes  a  .noticeable  attempt  to  move  the  trouble 
is  probably  something  of  this  mechanical  nature. 

"Short  Circuits. — If,  however,  large  current  is  indicated  and 
the  motor  remains  absolutely  inert,  the  trouble  is  electrical,  and 
the  inference  is  that  the  current  does  not  go  through  the  motor 
at  all.  Lift  one  of  the  motor  brushes  and  try  the  vehicle  again. 
If  the  large  current  is  still  indicated,  the  inference  becomes  a 
certainty.  This  trouble  is  known  as  short  circuit,  that  is  to  say, 
a  spurious  path  for  the  current  which  deflects  it  out  of  the  motor. 


DYNAMOS  AND    MOTORS. 


671 


STOPS  TURNS  AT 

DOUBLE  SPEED 


STOPS 


STOPS 


-III 


l/vwv 


STOPS 


STOPS 


IAMA/I 


TURNS 


PIG.  421.— Diagram  of  Common  Motor  Troubles,  as  described  in  the  tent 


572 


SELF-PROPELLED   VEHICLES. 


In  the  controller  may  be  sought: 

"A.  Foreign  pieces  of  metal  making  contact  between  portions 
of  the  electrical  circuit. 

"B.  Loose  fingers  which  may  make  contact  with  wrong  parts  of 
the  controller  or  with  each  other. 

"C.  Dirt  between  the  fingers  or  contacts. 

"D.  Breaks  in  the  insulation  permitting  the  wires  to  make  con- 
tact with  adjacent  metal  or  with  each  other. 

"If  the  controller  appears  to  be  all  right,  look  in  the  motor  for : 

"A.  Broken  insulation,  allowing  the  bare  wires  to  touch  the 
frame  or  each  other. 


FIG.  422.— Diagram  Showing  the  Operative  Conditions  of  a  Dynamo  Generator  and  Elec- 
trical Motor.    The  machine  on  the  left  is  the  dynamo,  that  on  the  right  the  motor. 

"B.  Dirt  between  contacts  or  between  live  metal  and  the  motor 
frame. 

"C.  Foreign  materials  bridging  contacts. 

"In  such  a  case  it  is  sometimes  of  assistance  to  turn  on  the 
current  for  an  instant.  The  defective  place  may  betray  its  lo- 
cality by  a  smoke  or  spark. 

"If,  when  the  brush  is  lifted,  and  the  vehicle  tried,  the  ex- 
cessive current  indication  disappears,  /f.here  are  but  two  electrical 
troubles  that  are  possible : 

"A.  The  magnet  coils  of  the  motor  may  be  short  circuited. 

"B.  The  ammeter  may  not  be  reading  correctly. 

"The  latter  trouble  is  least  likely ;  the  former  should  be  sought 
first. 


DYNAMOS  AND   MOTORS.  573 

"A  series  motor  with  a  short  circuited  magnet  coil  will  call 
for  a  large  current  but  will  do  nothing  with  it.  Therefore,  exam- 
ine the  magnet  coil  terminals  for  troubles  of  this  nature. 

"A  short  circuit  may  exist  even  if  the  ammeter  does  not  in- 
dicate it.  In  such  a  case  it  is  usually  found  in  the  controller, 
which  sparks  heavily  when  operated,  although  the  vehicle  does 
not  move.  This  combination  of  phenomena  also  indicates  im- 
proper connection  of  the  batteries,  as  has  been  previously  ex- 
plained. 

"An  excessive  call  for  current  is  accompanied  with  a  drop  in 
the  voltmeter  indication. 


FIG.  423.— General  Electric  Motor,  Designed  for  Heavy  Vehicle  Use,  with 
single  or  double  reduction.  Capacity,  30  amperes  at  85  volts;  800  R.  V.  M, 
at  full  load. 

"Two- Motor  Troubles. — With  a  two-motor  equipment  the 
difficulties  that  may  arise  differ  but  little.  A  few  which  are 
peculiar  to  this  type  may  be  mentioned.  Such  motors  are  some- 
times run  in  two  ways.  The  first  notch  connects  the  motors  in 
series,  while  the  higher  speed  notches  connect  the  motors  in 
parallel.  If  one  of  the  motors  open-circuits  on  a  series  notch, 
the  vehicle  stops,  for  the  entire  motive  circuit  is  broken.  If  it 


574 


SELF-PROPELLED   VEHICLES. 


open-circuits  on  a  parallel  notch,  that  motor  stops  and  the  other, 
with  its  circuit  to  the  batteries  intact,  continues  to  run  and  may 
cause  the  vehicle  to  make  some  abrupt  and  unexpected  turns.  If 
either  of  the  motors  gets  short-circuited,  the  exact  converse  takes 
place.  If  the  accident  occurs  on  a  series  notch  the  unimpaired 
motor  continues  to  run,  and,  it  may  be  added,  at  nearly  double  its 
previous  speed.  If  it  occurs  on  a  parallel  notch  a  short  circuit  on 
one  motor  constitutes  a  short  circuit  on  the  other  also,  and  if  the 
short  circuit  is  sufficiently  severe  both  motors  will  stop,  even 
though  an  enormous  current  may  be  drawn  from  the  batteries." 


Fio.424.— Type  of  General  Electric  Light  Vehicle  Motor,  with  ra>o  open,  showing 
commutator  and  brush  apparatus.  The  pinion  end  head  is  arranged  for  double 
reduction.  Both  end  heads  and  gear  housing  are  made  of  aluminum.  Suspension 
by  lugs  to  body.  Capacity,  31)^  amperes  at  39  volts ;  1,800  B.  P.  M.  at  full  load. 


CHAPTER  FORTY-THREE. 

STORAGE  BATTERIES. 

Introduction. — Storage  batteries  are  generally  described  as 
being  devices  for  storing  electric  energy,  which  may  be  utilized 
subsequently  for  various  purposes.  The  term  accumulators  is 
sometimes  applied  from  the  fact  that  they  "accumulate"  electric 
energy  when  charged  from  an  outside  source.  Storage  batteries 
are  also  called  secondary  batteries  to  distinguish  them  from  bat- 
teries of  the  primary  type. 

Secondary  batteries  are  in  no  sense  generators  of  electricity  but  are 
employed  to  accumulate  a  given  quantity  of  electric  energy,  the  quantity 
of  which  is  estimated  by  the  number  of  hours  required  to  discharge  it  at 
a  given  rate. 

The  General  Theory  of  Storage  Batteries. — The  general 
theory  upon  which  a  secondary  battery  operates  was  discovered  as 
early  as  1801,  when  Gautherot  discovered  that  if  two  plates  of 
platinum  or  silver,  immersed  in  a  suitable  electrolyte,  be  con- 
nected to  the  terminals  of  an  active  primary  cell  and  current  is 
allowed  to  flow  for  any  desired  period,  a  small  current  could  be 
obtained  on  an  outside  circuit  connecting  these  two  electrodes, 
as  soon  as  the  primary  battery  had  been  disconnected.  The 
process  which  takes  place  in  this  case  is  briefly  as  follows : 

An  electrolyte,  consisting  of  a  weak  solution  of  sulphuric  acid,  permits 
ready  conduction  of  the  current  from  the  primary  battery,  the  greater 
the  proportion  of  acid  in  certain  limits  the  smaller  being  the  resistance 
offered. 

The  effect  of  the  current  passing  through  the  electrolyte  is  the  decom- 
position of  the  water,  which  is  indicated  by  the  formation  of  bubbles 
upon  the  exposed  surfaces  of  both  electrode  sheets,  these  bubbles  being 
formed  by  oxygen  gas  on  the  plate  connected  to  the  positive  pole  of  the 
primary  battery  and  hydrogen  on  the  plate  connected  to  the  negative  pole 
of  the  battery. 

Because,  however,  the  oxygen  is  unable  to  attack  either  platinum  or 
silver  under  such  conditions,  the  capacity  of  such  a  device  to  act  as  an 
electrical  accumulator  is  practically  limited^  to  the  point  at  which  both 
plates  are  covered  with  bubbles.  After  this  point  the  gases  will  begin 
to  escape  into  the  atmosphere. 

575 


576  SELF-PROPELLED  VEHICLES. 

In  this  simple  apparatus,  as  in  the  storage  cells  manufactured  at  the 
present  day,  the  prime  condition  to  operation,  is  that  the  resistance  of  the 
electrolyte  should  be  as  low  as  possible  in  order  that  the  current  may 
pass  freely  and  with  full  effect  between  the  electrodes.  If  the  resistance 
of  the  electrolyte  be  too  small,  the  current  intensity  will  cause  the  water 
to  boil  rather  than  to  occasion  the  electrolytic  effects  noted  above. 

As  soon  as  the  current  from  the  primary  cell  is  discontinued,  and  the 
two  electrode  plates  from  the  secondary  cell  are  joined  by  an  outside  wire, 
a  small  current  will  be  caused  to  flow  upon  that  outside  circuit  by  the 
recomposition  of  the  acid  and  water  solution.  The  process  is  in  a  very 
definite  sense  a  reversal  of  that  by  which  the  current  is  generated  in  a 
primary  cell. 


FIG.  425.— One  Plate,  or  "Grid,"  of  a  Type  of  Storage  Cell  constructed  by 
inserting  buttons  or  ribbons  of  the  proper  chemical  substances  in  perfo- 
rations. Some  such  cells  use  crimped  ribbons  of  metallic  lead  for  in- 
serting in  the  perforations,  others  pure  red  lead  or  other  suitable 
material. 

Hydrogen  collected  upon  the  negative  plate,  which  was  the  cathode,  so 
long  as  the  primary  battery  was  in  circuit,  is  given  off  to  the  liquid  im- 
mediately surrounding  it,  uniting  with  its  particles  of  oxygen  and  causing 
the  hydrogen,  in  combination  with  them,  to  unite  with  the  particles  of 
oxygen  next  adjacent,  continuing  the  process  until  the  opposite  positive 
plate  is  reached,  when  the  oxygen  collected  there  is  finally  combined  with 
the  surplus  hydrogen,  going  to  it  from  the  surrounding  solution. 

This  chemical  process  causes  the  current  to  emerge  from  the  positive 
plate,  which  was  the  anode,  so  long  as  the  primary  battery  was  in  circuit. 
The  current  thus  produced  will  continue  until  the  recomposition  of  the 
gases  is  complete ;  then  ceasing  because  these  gases,  as  before  stated,  do 
not  combine  with  the  metal  of  the  electrodes. 

Plate  Material. — The  material  from  which  storage  battery 
plates  are  made  depends  largely  upon  the  use  to  which  they  are 


STORAGE  BATTERIES.  577 

to  be  adapted.  Batteries  are  now  being  manufactured  with  plates 
made  of  iron  and  nickel,  lead  and  zinc,  and  lead  and  lead,  the 
latter  being  used  almost  exclusively. 

In  batteries  of  this  class  the  negative  plates  are  made  of  sponge  lead, 
which  has  a  light  gray  color  and  is  very  soft.  The  positive  plates  are 
of  peroxide  of  lead,  being  dull  chocolate  in  color  and  hard  in  texture. 


FIG.  426.— "Unformed"  Plate  of  One  Pattern  of  "Gould"  Storage  OelL  The 
particular  plate  shown  has  total  outside  dimensions  of  6x6  inches. 
The  clear  outline  of  the  grooves  indicates  absence  of  oxides,  due  to 
action  of  "forming"  solutions,  or  charging  current. 

Types  of  Storage   Batteries. — In  general  storage  batteries 
may  be  divided  into  two  classes : 

1.  The  Plante; 

2.  The  Faure. 

The  difference  is  principally  in  the  method  of  constructing  the 
plates. 

In  the  Plante  type,  the  lead  is  chemically  attacked  and  finally 
converted  into  lead  peroxide,  probably  after  it  has  gone  through 


578 


SELF-PROPELLED  VEHICLES. 


several  intermediate  changes.  The  plates  are  all  formed  as 
positive  plates  first  and  then  all  that  are  intended  for  negatives 
are  reversed,  the  peroxide  being  changed  into  sponge  lead. 

In  order  to  make  this  type  of  plate  more  efficient,  and  its  formation 
more  rapid,  the  surfaces  are  finely  subdivided,  the  following  methods  being 
those  most  common :  scoring,  grooving,  laminating,  casting,  pressing  and 
by  the  use  of  a  lead  wool. 


FIG.  427.-One  Cell  of  the  "Gould"  Storage  Battery  for  Electric  Vehicle  Use. 
According  to  the  data  given  by  the  manufacturers,  this  cell,  containing 
four  negatives  and  three  positive  plates,  has  a  normal  charging  rate  of 
27  amperes;  a  distance  rate  of  22 y*  amperes  for  4  hours;  a  capacity  of 
81  ampere-hours  at  3  hours'  discharge,  and  of  90  ampere-hours  at  4 
hours'  discharge.  The  plates  are  each  5%x7J4  inches,  and  the  total  di- 
mensions of  the  cell,  enclosed  in  its  rubber  jar,  are  2^x6J4xll  inches. 
Forty  such  cells  are  generally  used  for  an  average  light  vehicle  battery. 

The  Faure  or  pasted  type  is  one  which  is  formed  by  attaching 
the  active  material  by  some  mechanical  means  to  the  grid  proper. 
The  active  material  first  used  for  this  purpose  was  red  lead,  which 
was  reduced  in  a  short  time  to  lead  peroxide  when  connected  as 
the  positive  or  anode,  or  to  spongy  metallic  lead  when  connected 
as  the  cathode  or  negative,  thus  forming  plates  of  the  same 
chemical  compound  as  in  the  Plante  type. 


STORAGE  BATTERIES. 


579 


The  materials  used  at  the  present  time  by  the  manufacturers 
for  making  this  paste  are  very  largely  a  secret  with  them,  but  in 
general  they  consist  of  pulverized  lead  or  lead  oxide  mixed  with 
some  liquid  to  make  a  paste. 

The  Faure  plates  'are  usually  lighter  and  of  higher  capacity  than  the 
Plante,  but  have  a  tendency  to  shed  the  material  from  the  grid,  thus 
making  the  battery  useless. 


FIG.  428.—  A  Typical  Storage  Cell  Enclosed  in  a  Glass  Jar.  This  cell  repre- 
sents one  of  the  best-known  makes  of  the  PlantS  genus.  With  five 
plates,  as  shown,  such  a  cell  has  a  capacity  of  80  ampere-hours,  at  8 
hours'  discharge;  of  70  ampere-hours,  at  5  hours'  discharge;  of  60  am- 
pere-hours, at  3  hours'  discharge,  with  a  discharge  rate  of  10  amperes 
in  8  hours;  of  14  amperes  in  5  hours,  and'  of  20  amperes  in  3  hours.  The 
total  outside  dimensions  of  this  cell  are  5^x9^x11/4  inches;  dimensions 
of  each  plate's  active  surface,  7}4x7%  inches. 


Many  ways  have  been  tried  for  mechanically  holding  the  active  material 
to  the  grid,  the  general  method  being  by  a  special  design  in  the  shape  of 
the  grid.  Some  of  these  designs  are  solid  perforated  sheets  or  lattice 
work  ;  corrugated  and  solid  recess  plates  not  perforated  ;  ribbed  plates 
with  projecting  portions;  grid  cast  around  active  material;  lead  envelopes; 
triangular  troughs  as  horizontal  ribs. 


580 


SELF-PROPELLED   VEHICLES. 


fc  fc 


STORAGE  BATTERIES.  581 

Points  on  Care  and  Operation. — On  the  manner  of  operating 
and  maintaining  storage  batteries  for  use  in  electric  vehicles  and 
for  other  purposes,  there  are  a  number  of  points  to  be  considered. 

However,  since  full  directions  are  always  furnished  by  manu- 
facturers with  each  set  of  cells,  it  is  necessary  to  give  only  the 
merest  outlines  here. 

The  electrolyte  usually  consists  of  I  part  of  chemically  pure  con- 
centrated sulphuric  acid  mixed  with  several  parts  of  water.  The  propor- 
tion of  water  differs  with  the  several  types  of  cell  from  three  parts  to 
eight  parts,  as  specified  in  the  directions  accompanying  the  cells.  In 
making  the  mixture  it  is  necessary  to  use  an  hydrometer  to  test  the 
specific  gravity  of  both  the  acid  and  the  solution.  The  most  suitable  acid 
should  show  a  specific  gravity  of  about  1.760,  or  66°  Baume. 

The  mixture  should  be  made  by  pouring  the  acid  slowly  into 
the  water,  never  the  reverse.  As  cannot  be  too  strongly  stated, 
it  is  very  dangerous  to  pour  the  water  into  the  acid;  the  latter  is 
corrosive  and  will  painfully  burn  the  flesh. 

Distilled  or  rain  water  should  be  used  in  preparing  the  electrolyte.  When 
made,  the  solution  should  be  allowed  to  cool  for  several  hours  or  until' 
its  temperature  is  approximately  that  of  the  atmosphere  (60°  being  the 
average).  At  this  point  it  should  have  a  specific  gravity  of  about  1,200 
or  25°  Baume.  If  the  hydrometer  show  a  higher  reading,  water  may 
be  added  until  the  correct  reading  is  obtained;  if  a  lower  reading,  dilute 
acid  may  be  added  with  similar  intent. 

The  electrolyte  should  never  be  mixed  in  jars  containing  the  battery 
plates,  but  preferably  in  stone  crocks,  specially  prepared  for  the  purpose. 
Furthermore,  it  should  never  be  placed  in  the  cell  until  perfectly  cool. 

As  soon  as  possible  after  placing  the  electrolyte  in  the  cell,  the  charging 
current  should  be  applied. 

Connections  for  Charging. — In  charging  a  storage  battery,  it 
is  of  prime  importance  that  the  connections  with  the  generator  be 
properly  arranged.  This  means  that  the  positive  pole  of  the  gen- 
erator should  be  invariably  connected  to  the  positive  pole  of  the 
secondary  battery — which  is  to  say,  the  pole  which  is  positive  in 
action  when  the  current  is  emerging  from  the  secondary  battery, 
or  the  pole  that  is  connected  to  the  positive  plates. 

An  error  in  making  the  connections  will  result  in  entire  de- 
rangement of  the  battery  and  its  ultimate  destruction. 

In  charging  a  storage  battery  for  the  first  time  it  is  essential  that  the 
current  should  be  allowed  to  enter  at  the  positive  pole  at  about  one-half 
the  usual  charging  rate  prescribed ;  but  after  making  sure  that  all  neces- 
sary conditions  have  been  fulfilled,  it  is  possible  to  raise  the  rate  to  that 
prescribed  by  the  manufacturers  of  the  particular  battery. 


582  SELF-PROPELLED   VEHICLES. 

Portable  Instruments  used  with  Batteries. — The  following 
outfit  should  be  obtained  for  use  in  charging  batteries: 

1.  Hydrometer  Syringe  (specific  gravity  tester)  ; 

2.  Acid  testing  set  (can  be  used  instead  of  syringe)  ; 

3.  Low  reading  voltmeter  and  suitable  prods; 

4.  Thermometer. 

Period  of  Charging  a  New  Battery. — With  several  of  the 
best  known  makes  of  the  storage  battery  the  prescribed  period 
for  the  first  charge  varies  between  twenty  and  thirty  hours.  The 
manufacturers  of  a  well  known  cell  of  the  Plante  genus  prescribe 
for  the  first  charge,  half  rate  for  four  hours,  after  which  the  cur- 
rent may  be  increased  to  the  normal  power  and  continued  for 
twenty  hours  successively. 

The  strength  of  current  to  be  used  in  charging  a  cell  should 
be  in  proportion  to  its  own  ampere  hour  capacity. 

Thus,  as  given  by  several  manufacturers  and  other  authorities,  the  nor- 
mal charging  rate  for  a  cell  of  400  ampere  hours  should  be  fifty  amperes; 
or  one-eighth  of  its  ampere  hour  rating  in  amperes  of  charging  current. 

Before  closing  the  charging  circuit  it  is  essential  that  the  voltage  of  the 
generator  should  be  at  least  ten  per  cent,  higher  than  the  normal  voltage 
of  the  battery  when  charged.  The  fact  that  a  storage  cell  is  fully  charged 
is  evident  by  the  apparent  boiling  of  the  electrolyte  and  a  free  giving- 
off  of  gas.  It  may  also  be  determined  by  the  voltmeter,  which  will  show 
whether  the  normal  pressure  has  been  attained.  At  the  first  charge  of 
the  battery  the  voltage  should  be  allowed  to  rise  somewhat  above  the 
point  of  normal  pressure,  but  thereafter  should  be  discontinued  at  a  speci- 
fied point. 

At  the  first  charging  of  a  cell,  when  the  pressure  has  reached  the  re- 
quired limit,  the  cell  should  be  discharged  until  the  voltage  has  fallen  to 
about  two-thirds  normal  pressure,  when  the  cell  should  again  be  recharged 
to  the  normal  voltage  (2.5  or  2.6  volts). 

Care  should  be  taken  in  charging  a  battery  not  to  have  a  naked 
flame  anywhere  in  its  vicinity. 

To  either  discharge  or  charge  a  battery  at  too  rapid  a  rate  involves  the 
generation  of  heat.  Thus,  while  this  is  not  liable  to  result  in  flame  under 
usual  conditions,  the  battery  may  take  fire,  if  it  be  improperly  connected 
or  improperly  used. 

Changed  Specific  Gravity  of  the  Electrolyte. — Another 
effect  resulting  from  the  first  charging  of  a  storage  cell  is  a 


STORAGE,  BATTERIES. 


583 


change  in  the  specific  gravity  of  the  electrolyte.  According  to  the 
figures  already  given,  this  should  be  about  1,200,  when  the  solu- 
tion is  first  poured  into  the  cells. 

At  the  completion  of  the  first  charge,  it  should,  on  the  same  scale,  be 
about  1,225.  If  it  be  higher  than  this,  water  should  be  added  to  the 
solution  until  the  proper  figure  is  reached;  if  it  be  lower,  dilute  sulphuric 
acid  should  be  added  until  the  hydrometer  registers  1,225. 

In  charging  a  storage  cell,  particularly  for  the  first  time,  it  is  desirable 
to  remember  that  a  weaker  current  than  that  specified  may  be  used  with 
the  same  result,  provided  the  prescribed  duration  of  the  process  be 
proportionally  lengthened.  The  battery  may  also  be  charged  beyond  the 
prescribed  voltage,  ten  or  twenty  per  cent,  overcharge  effecting  no  injury 
occasionally;  although,  if  frequently  repeated,  it  seriously  shortens  the 
life  of  the  battery. 


fia.  431. — The  Exide  storage  cell.  The  positive  and  negative  plates  are  separated  by  thin 
sheets  of  perforated  hard  rubber,  placed  on  both  sides  of  each  positive  plate.  The 
electrolyte  and  plates  are  contained  in  a  hard  rubber  jar. 

Fia.  432. — An  Exide  battery  of  five  cells.  The  box  which  holds  the  cells  is  usually  made 
of  »ak,  properly  reinforced,  with  the  wood  treated  to  render  it  acid  proof.  The  ter- 
minals, as  shown,  consist  of  metal  castings  attached  to  the  side  of  the  box  and  plainly 
marked. 

Another  point  of  importance  touches  the  question  of  maintaining  the 
charge  of  the  battery.  Even  if  the  use  be  only  slight  in  proportion  to 
the  output  capacity,  the  battery  should  be  charged  at  least  once  in  two 
weeks,  in  order  to  maintain  it  at  the  point  of  highest  efficiency.  About 
as  often,  a  battery  should  be  charged  at  slowest  rate,  the  charging  cur- 
rent being  adjusted  to  complete  the  charge  only  in  twenty  or  thirty  hours. 

In  charging  a  storage  battery,  it  is  essential  to  remember  the 
fact  that  the  normal  charging  rate  is  in  proportion  to  the  voltage 
of  the  battery  itself. 


584:  SELF-PROPELLED   VEHICLES. 

Thus,  a  loo-ampere-hour  battery,  charged  from  a  no  volt  circuit,  at  the 
rate  of  ten  amperes  per  hour,  would  require  ten  hours  to  charge,  and 
would  consume  in  that  time  an  amount  of  electrical  energy  represented 
by  the  product  of  no  (voltage)  by  10  (amperes)  which  would  give  1,100 
watts. 

Old  Electrolyte. — The  electrolyte  may  be  saved  and  used  when 
reassembling  the  battery,  provided  great  care  be  exercised  when 
pouring  it  out  of  the  jar,  so  as  not  to  draw  off  with  it  any  of  the 
sediment.  It  should  be  stored  in  convenient  receptacles,  prefer- 
ably carboys,  which  have  been  thoroughly  washed  and  never  used 
for  any  other  purpose. 

The  electrolyte  saved  in  this  manner  will  not,  however,  be  sufficient  to 
refill  the  battery,  and  as  some  new  electrolyte  will  be  required,  in  general 
it  is  recommended  that  the  old  supply  be  thrown  away  and  all  new  elec- 
trolyte (1,200  specific  gravity)  be  used  when  reassembling. 

Charge  Indications. — The  state  of  the  charge  is  not  only  in- 
dicated by  the  density  of  the  electrolyte  and  the  voltage  of  the 
cell,  but  also  by  the  color  of  the  plates,  which  is  considered  by 
many  authorities  as  one  of  the  best  tests  for  ascertaining  the 
condition  of  a  battery. 

In  the  case  of  formed  plates,  and  before  the  first  charging,  the  positives 
are  of  a  dark  brown  color  with  whitish  or  reddish  gray  spots  and  the 
negatives  are  of  a  yellowish  gray.  _  The  whitish  or  reddish  gray  spots  on 
the  positive  plates  are  small  particles  of  lead  sulphate  which  have  not 
been  reduced  to  lead  peroxide  during  the  process  of  forming,  and  repre- 
sent imperfect  sulphatation. 

As  a  general  rule  the  first  charging  should  be  carried  on  until  these 
spots  completely  disappear.  After  this  the  positive  plates  should  be  of  a 
dark  red  or  chocolate  color  at  the  end  of  a  discharge  and  of  a  wet  state 
or  nearly  black  color  when  fully  charged.  A  very  small  discharge  is 
sufficient,  however,  to  change  them  from  black  to  the  dark  red  or  chocolate 
color. 

If  the  battery  has  been  discharged  to  a  potential  lower  than  1.8  volts, 
the  white  sulphate  deposits  will  reappear  turning  the  dark  red  color  to  a 
grayish  tint  in  patches  or  all  over  the  surface  of  the  plate,  or  in  the  form 
of  scales  of  a  Venetian  red  color. 

The  formation  of  these  scales  during  charging  indicates  that 
the  maximum  charging  current  is  too  large  and  should  be  re- 
duced until  the  scales  or  white  deposits  fall  off  or  disappear,  after 
which  the  current  can  be  increased  again. 


STORAGE,  BATTERIES.  585 

During  charging,  the  yellowish  gray  color  of  the  negatives  changes  to 
a  pale  slate  color  which  grows  slightly  darker  at  the  completion  of  the 
charge.  The  color  of  the  negatives  always  remains,  however,  much 
lighter  than  that  of  the  positives. 

The  Capacity  of  Storage  Batteries. — The  discharge  capacity 
of  a  storage  battery  is  stated  in  ampere-hours,  and  unless  other- 
wise specified,  refers  to  its  output  of  current  at  the  8-hour  rate. 
Most  manufacturers  of  automobile  batteries  specify  only  the 
amperage  of  the  discharge  at  3  and  4  hours. 

As  there  is  no  sure  way  for  the  automobilist  to  estimate  the 
discharge  capacity  of  his  battery,  he  is  obliged  to  base  such  calcu- 
lations as  he  makes  on  the  figures  furnished  by  the  manufacturers. 
With  the  help  of  his  indicating  instruments — the  voltmeter  and 
ammeter. 

It  is  customary  to  state  the  normal  capacity  of  a  cell  in  ampere-hours, 
based  upon  the  current  which  it  will  discharge  at  a  constant  rate  for  eight 
hours. 

Thus  a  cell  which  will  discharge  at  10  amperes  for  8  hours  without  the 
voltage  falling  below  1.75  per  cell  is  said  to  have  a  capacity  of  8p  ampere- 
hours.  It  does  not  follow  that  80  amperes  would  be  secured  if  the  cell 
were  discharged  in  i  hour.  It  is  safe  to  say  that  not  more  than  40  amperes 
would  be  the  result  with  this  rapid  discharge. 

The  ampere-hour  capacity  decreases  with  the  increase  In  current 
output.  An  80  ampere-hour  cell,  capable  of  delivering  10  amperes  for 
8  hours,  would,  when  discharged  at  14  amperes,  have  a  capacity  of  701 
ampere-hours;  when  discharged  at  20,  its  capacity  would  be  60;  and  when 
discharged  at  40,  its  capacity  will  have  decreased  from  80  to  40  ampere- 
hours. 

Generally  speaking,  the  voltage  during  discharge  is  an  indication  of  the 
quantity  of  electricity  remaining  within  the  cell. 

Apart  from  any  considerations  of  efficiency,  the  driver  of  an 
electric  carriage  should  carefully  bear  in  mind  the  figures  supplied 
by  the  manufacturers  of  the  type  of  battery  he  uses,  in  order  to 
judge : 

1.  How  long  the  present  charge  will  last ; 

2.  Whether  he   is   exceeding   the   normal   rate   of  discharge,   and   thus 
contributing  to  the  unnecessary  waste  of  his  battery  and  incurring  other 
dangers  that  may  involve  unnecessary  expense. 

As  a  general  rule  the  i-hour  discharge  rate  is  four  times  that  of  the 
normal,  or  8-hour  discharge,  and  considerations  of  economy  and  prudence 


586  SELF-PROPELLED  VEHICLES. 

suggest  that  it  should  never  be  exceeded,  if,  indeed,  it  is  ever  employed. 
The  3-hour  discharge,  which  is  normally  twice,  that  of  the  8-hour,  is 
usually  the  highest  that  is  prudent  while  the  4-hour  discharge  is  the  one 
most  often  employed  for  average ^ high-speed  riding;  batteries  give  only 
the  3  and  4-hour  discharge  rates  in  specifying  the  capacity  of  their  pro- 
ducts. 

High  Charging  Rates. — Occasionally  it  is  desirable  to  charge 
a  battery  as  quickly  as  possible,  in  order  to  save  time,  as  when 
belated  and  far  from  home  with  an  electric  vehicle  that  has  almost 
reached  its  limit. 

As  a  general  rule,  such  a  procedure  should  not  be  adopted  unless  the 
battery  is  thoroughly  discharged. 


FIG.  433. — Elwell-Parker  Motor  Generator  Set  lor  charging  Vehicle  Storage 
Batteries.  This  machine  has  an  output  capacity  of  about  15  horse 
power. 

In  charging1  a  battery  at  a  high  rate,  the  danger  to  be  avoided 
is  the  tendency  of  the  cells  to  heat. 

A  battery  should  never  be  charged  at  a  high  rate  unless  it  be 
completely  exhausted,  since  it  is  a  fact  that  the  rate  of  charge 
that  it  will  absorb  is  dependent  upon  the  amount  of  energy  al- 
ready absorbed. 


STORAGE  BATTERIES. 


587 


Battery=Charging  Apparatus. — A  storage  battery  may  be 
charged  from  direct  current  mains  having  the  proper  voltage  if, 
as  is  not  always  possible,  such  a  circuit  be  available.  Since,  how- 
ever, a  current  of  as  great  uniformity  as  possible  is  required,  and 
existing  conditions  must  be  met  in  each  separate  case,  it  is  the 


FIG.  434.— Waverley  Motor-generator  Charging  Set  for  Use  on  a  Single- 
phase  Alternating  Current  Circuit  of  100  to  110  Volts  (60  Cycles).  This 
apparatus  will  give  a  current  of  15  amperes  at  65  volts  In  charging  a 
24-cell  battery,  or  10  amperes  in  charging  a  30-cell  battery. 

rule  to  use  a  motor-generator  set  with  a  regulating  switchboard. 
Such  an  apparatus  consists  of  a  direct  current  dynamo,  driven 
direct  from  the  shaft  of  a  motor,  which,  in  turn,  is  energized  by 
current  from  the  line  circuit. 


588 


SELF-PROPELLED   VEHICLES. 


With  a  direct  current  on  the  line,  a  direct-current  motor  may  be  used; 
but  with  an  alternating  current  an  induction  motor  is  required.  The 
speed  of  the  motor  is  governed  by  a  rheostat,  and  the  output  of  the 
dynamo  is  thus  regulated  as  desired. 

Method  of  Operating. — An  idea  of  the  procedure  involved  in 
the  use  of  such  an  apparatus  may  be  obtained  from  the  following 
items  furnished  by  the  General  Electric  Company's  outfits : 

I.  Pull  down  the  tripping  handle  of  the  circuit  breaker  and  close  the 
two  outside  poles  which  connect  the  motor  circuit.  The  tripping  shaft  is 
then  automatically  locked  so  that  the  breaker  will  not  be  open.  Then  push 
the  core  of  the  low.  voltage  coil  (right-hand  coil)  up  as  far  as  it  will  go. 


FIGS.  435, 436.-Switchboard  and  Motor-generator  Circuit  Connections  for  Charg- 
ing a  Battery  from  Direct  Current  Mains. 

2.  Start  the  motor. 

3.  Regulate  the  generator  to  give  about  the  desired  charging  voltage. 

4.  Connect  cable  to  automobile  and  attach  to  panel  by  means  of  plug 
switch. 

5.  Raise  the  core  of  the  underload  coil   (left-hand  coil)    up  as  high  as 
it  will  go,  and  while  holding  in  this  position  close  the  other  two  poles 
of  the  circuit  breaker.     The  closing  of  these  two  poles  releases  the  lock 
on  the  tripping  shaft  so  that  the  breaker  will  then  operate  on  either  un- 
derload or  low  voltage. 

6.  Regulate    generator    voltage    until    ammeter    indicates    the    normal 
ampere  charging  rate  of  the  storage  battery. 


STORAGE,  BATTERIES. 


589 


Charging  Through  the  Night. — If,  after  a  late  evening  run, 
the  vehicle  will  be  wanted  early  the  next  morning1,  the  battery 
may  be  charged  during  the  night  without  an  attendant  being 
present;  but  in  doing  this  great  care  must  be  taken  not  to  ex- 
cessively overcharge. 

A  careful  estimate  of  the  amount  of  current  required  should 
be  made  and  the  rate  of  charge  based  on  this  estimate. 

If,  say,  72  ampere  hours  be  required  to  recharge,  and  the  time  available 
is  nine  hours,  the  average  rate  of  charge  must  be  8  amperes. 


voltmeter 


'i/9  Sw/ten 


FIGS.  437.  438.-Switchboard  and  Motor-generator  Circuit  Connections  for 
Charging  a  Battery  from  Alternating  Current  Mains.  The  connections 
of  a  third  wire  are  shown,  for  use  in  case  a  three-phase  circuit  is 
available. 

If  charging  from  a  110-volt  circuit,  the  rate  at  the  start  should  be  about 
10  amperes ;  if  from  a  soo-volt  circuit,  about  9  amperes ;  as,  in  charging 
from  a  source  with  constant  voltage,  such  as  a  lighting  or  trolley  circuit, 
the  rate  into  the  battery  will  fall  as  the  charge  progresses.  This  also 
applies  if  the  charging  be  done,  without  attendance,  from  a  mercury  arc 
rectifier. 

Charging  Batteries  Out  of  Vehicles. — When  a  battery  is 
being  overhauled  or  is  out  for  cleaning,  it  may  be  more  conven- 
ient or  suitable  to  charge  it  while  out  of  the  vehicle. 


590  SELF-PROPELLED   VEHICLES. 

In  such  a  case  the  cells  must  be  connected  together  in  series  and  to  the 
charging  source  in  relatively  the  same  manner  as  if  they  were  in  the 
vehicle;  that  is,  the  positive  (+)  terminal  of  one  group  of  cells  must 
be  connected  to  the  negative  ( — )  terminal  of  the  next  group,  and  the  two 
free  terminals,  one  positive  and  the  other  negative,  must  be  connected 
respectively  to  the  positive  and  negative  terminals  of  the  charging  cir- 
cuit, but  not  until  all  of  the  groups  have  been  connetced  in  series. 

Great  care  must  always  be  taken  to  have  the  polarities  correct 
and  the  wire  or  cable  for  the  connections  of  ample  size  to  carry, 
without  heating,  the  heaviest  current  used  in  charging-.  The  size 
used  in  the  vehicle  will  be  proper. 

The  operation  of  charging  is  then  carried  on  in  precisely  the  same  man- 
ner as  if  the  battery  were  in  the  vehicle. 

Short  Circuiting. — A  form  of  derangement  that  may  occa- 
sionally affect  the  vehicle  batteries  is  short  circuiting.  It  may 
be  caused  by  some  of  the  active  material — if  the  cell  be  of  the 
pasted  variety — scaling  off  and  dropping  between  the  plates,  or 
by  an  over  collection  of  sediment  in  the  bottom  of  the  cell. 

Should  the  operator  suspect  trouble  with  his  battery  he  may  discover 
a  short  circuited  cell  by  the  marked  difference  in  color  of  the  plates  or 
of  the  specific  gravity  of  the  electrolyte,  as  compared  with  the  other  cells. 
No  particular  damage  will  be  caused,  if  the  trouble  be  discovered  and  re- 
moved before  these  symptoms  become  too  marked. 

If  a  foreign  substance  has  become  lodged  between  the  plates,  it  may  be 
removed  by  a  wood  or  glass  instrument. 

If  some  of  the  active  material  has  scaled  off,  it  may  be  forced  down  to 
the  bottom  of  the  jar.  If  excessive  sediment  be  found,  the  jar  and  plates 
should  be  washed  carefully,  and  reassembled. 

A  cell  that  has  been  short  circuited  may  be  disconnected  from 
the  battery  and  charged  and  discharged  several  times  separately, 
which  may  remedy  the  trouble. 

Batteries  Used  but  Occasionally. — If  a  battery  is  not  to  be 
used  for  several  days,  it  should  first  be  fully  charged  before  stand- 
ing; if  it  continue  idle,  a  freshening  charge  should  be  given 
every  two  weeks,  continuing  the  charging  when  the  cells  begin 
to  gas  freely. 

In  standing  idle  for  some  time,  a  battery  loses  part  of  its  charge,  due 
to  local  losses  in  the  cells,  which  the  freshening  charges  may  not  entirely 
overcome;  so  that  several  discharges  may  be  required  to  regain  full 
capacity. 


STORAGE  BATTERIES.  591 

Lack  of  Capacity. — Should  there  be  a  decrease  in  the  speed  or 
mileage  of  a  vehicle,  the  falling  off  may  be  due  to  trouble  in  the 
running  gear,  in  the  motors,  in  the  connections  or  in  the  battery. 

If  the  current  consumption,  as  shown  by  the  meter,  be  greater  than 
normal,  the  vehicle  is  running  "hard,"  and  it  should  be  overhauled.  If, 
however,  the  current  consumption  be  normal,  there  may  be  poor  connec- 
tions or  trouble  in  the  battery. 

Falling  off  in  the  capacity  of  the  battery  can  always  be  traced  to  some 
cause,  and  when  it  gives  indications  that  something  is  wrong,  take  it  out 
of  the  vehicle  and  look  for  the  trouble. 

There  may  be  a  dry  cell,  due  to  a  leaking  jar;  some  or  all  of  the  cells 
may  be  in  a  state  of  incomplete  charge,  due  to  the  battery  having  been 
run  too  low  and  not  sufficiently  charged ;  or  the  plates  may  be  short  cir- 
cuited, either  by  the  sediment  (deposit  in  the  bottom  of  the  jar)  getting 
up  to  the  bottom  of  the  plates  or  by  something  that  has  fallen  into  the  cell. 

Short  circuits  in  a  cell  are  indicated  by  short  capacity,  low  voltage  and 
low  specific  gravity,  excessive  heating  and  evaporation  of  the  electrolyte. 

If  the  trouble  cannot  be  located  by  the  eye,  connect  the  battery  in  series, 
and  discharge  it  at  the  normal  rate,  through  suitable  resistance.  If  a 
suitable  rheostat  be  not  available  a  water  resistance  may  be  used. 

This  consists  of  a  receptacle  (which  must  not  be  of  metal)  filled  with 
very  weak  acid  solution  or  salt  water  in  which  are  suspended  two  metal 
plates,  which  are  connected  by  wires  through  an  ammeter.  The  current 
may  be  regulated  by  altering  the  distance  between  the  plates  or  by  vary- 
ing the  strength  of  the  solution.  As  the  discharge  progresses,  the  voltage 
will  gradually  decrease  and  it  should  be  frequently  read  at  the  battery 
terminals ;  as  soon  as  it  shows  a  sudden  drop  the  voltage  of  each  cell 
should  be  read  with  a  low  reading  voltmeter. 

While  the  readings  are  being  taken,  the  discharge  rate  should  be  kept 
constant  and  the  discharge  continued  until  the  majority  of  the  cells  read 
1.70  volts;  those  reading  less  should  be  noted.  The  discharge  should  be 
followed  by  a  charge  until  the  cells  which  read  1.70  volts  are  up ;  then 
the  low  cells  should  be  cut  out,  examined  and  the  trouble  remedied. 

If  the  electrolyte  be  low  in  specific  gravity,  assuming  that  there  are  no 
short  circuits,  due  to  sediment  or  other  cause,  it  is  evidence : 

1.  Of  sloppage  or  a  leaky  jar,  the  loss  having  been  replaced  with  water 
alone ; 

2.  Of  insufficient  charge,  overdischarge,  standing  in  a  discharged  con- 
dition or  a  combination  of  these  abuses ;  any  of  them  mean  that  there  is 
acid  in  combination  with  the  plates,  which   should  be  brought  out  into 
the  electrolyte  by  a  long  charge  at  quarter  the  normal  discharge  rate. 

The  low  cells  should  be  grouped  by  themselves  and  charged  as  a 
separate  battery,  care  being  taken  that  the  positive  strap  of  one  cell  is 
connected  to  the  negative  strap  of  the  adjoining  cell  and  that  the  charg- 
ing connections  are  properly  made.  If  there  be  not  sufficient  resistance  in 
the  charging  rheostat  to  cut  the  current  down  to  the  proper  point,  use 
water  resistance. 

While  a  cell  is  being  treated,  when  possible,  the  cover  should  be  re- 
moved (if  sealed,  the  compound  can  be  loosened  by  using  a  hot  putty 
knife). 


592  SELF-PROPELLED  VEHICLES. 

Disconnecting  Cells. — The  best  method  of  disconnecting  cells 
assembled  with  pillar  straps,  for  the  purpose  of  replacing  broken 
jars,  cleaning  or  taking  out  of  commission,  is  to  use  a  five-eighth 
inch  twist  drill,  in  a  carpenter's  brace,  boring  down  into  the  top 
of  the  pillar  about  one-quarter  inch;  then  pull  off  the  connector 
sleeve  from  the  pillar.  By  following  this  method,  all  parts  may  be 
used  again. 

When  cells  are  equipped  with  top  straps,  the  straps  should  be  cut  with 
a  sharp  knife  or  chisel  midway  between  the  cells. 

Taking  Batteries  out  of  Commission. — Where  a  battery  is  to 
be  out  of  service  for  several  months,  and  it  is  not  convenient  to 
give  it  the  freshening  charge  every  two  weeks,  it  should  be  taken 
out  of  commission. 

To  do  this,  proceed  as  follows :  Charge  the  battery  in  the  usual  manner, 
until  the  specific  gravity  of  the  electrolyte  of  every  cell  in  the  battery 
has  stopped  rising  over  a  period  of  one  hour  (if  there  be  any  low  cells, 
due  to  short  circuits  or  other  cause,  they  should  be  put  in  condition  be- 
fore the  charge  is  started,  so  that  they  will  receive  the  full  benefit  of  it)- 
Disconnect  the  cells,  remove  the  covers  (if  sealed,  loosen  compound  with 
a  hot  putty  knife),  remove  the  elements  from  the  jars,  place  on  their 
sides  with  the  plates  vertical,  slightly  spread  the  plates  apart  at  the  bot- 
tom, withdraw  the  separators  and  pull  the  positive  and  negative  groups 
apart.  Play  a  gentle  stream  of  water  on  them,  to  wash  off  the  electro- 
lyte, and  then  allow  them  to  drain  and  dry.*  The  positives,  when  dry, 
are  ready  to  be  put  away.  If  the  negatives,  in  drying,  become  hot  enough 
to  steam,  they  should  be  again  rinsed  or  sprinkled  with  clean  water  and 
then  allowed  to  dry  thoroughly. 

When  dry,  completely  immerse  the  negatives  in  electrolyte  (of  about 
1.275  specific  gravity),  and  allow  them  to  soak  for  three  or  four  hours. 
The  jars  may  be  used  for  this  purpose.  After  rinsing  and  drying,  they 
are  ready  to  be  put  away.  The  rubber  separators  should  be  rinsed  in 
water.  Wood  separators,  after  having  been  in  service,  will  not  stand 
much  handling  and  had  better  be  thrown  away.  If  it  be  thought  worth 
while  to  keep  them,  they  must  be  kept  immersed  in  water  or  weak  electro- 
lyte, and  in  reassembling  the  electrolyte  must  be  put  into  the  cells  im- 
mediately, as  wet  wood  separators  must  not  stand  exposed  to  the  air  for 
an  unnecessary  moment,  especially  when  in  contact  with  plates. 

When  putting  the  battery  into  commission,  it  should  be  treated  in  the 
same  manner  as  if  it  were  new,  and  the  regular  instructions  for  as- 
sembling and  putting  into  commission  a  new  battery  followed. 

*  If  the  active  material  in  the  negative  plates  extend  beyond  the  ribs  of  the  grid 
(the  supporting  frame),  it  should  be  at  once  pressed  back  into  place,  care  being  taken  to 
prevent  the  plates  from  drying  before  this  is  done.  The  most  suitable  and  convenient 
method  for  pressing  is  to  place  between  the  plates  smooth  boards  of  a  thickness  equal  to 
the  distance  between  the  plates  and  then  put  the  groups  under  pressure. 


STORAGE,  BATTERIES.  593 

Cleaning  Jars. — The  jars  should  be  thoroughly  cleaned  with 
fresh  water,  no  sediment  being  allowed  to  remain. 

Condensed  Rules  for  the  Proper  Care  of  Batteries. — The 

following  general  instructions  should  be  followed  in  the  care  and 
maintenance  of  batteries : 

>  i.  A  battery  must  always  be  charged  with  "direct"  current  and  in  the 
right  direction. 

2.  Be   careful   to  charge   at  the   proper   rates   and   to   give   the   right 
amount  of  charge;   do  not  undercharge  or  overcharge  to  an  excessive 

degree. 

3.  Do  not  bring  a  naked  flame  near  the  battery  while  charging  or  tm-' 

mediately  afterwards. 

4.  Do  not  overdischarge. 

5.  Do  not  allow  the  battery  to  stand  completely  discharged. 

6.  Voltage  readings  should  be  taken  only  when  the  battery  is  charging 
or  discharging;   if  taken  when  the  battery  is  standing  idle  they  are  of 
little  or  no  value. 

7.  Do  not  allow  the  battery  temperature  to  exceed  110°  Fahr. 

8.  Keep  the  electrolyte  at  the  proper  height  above  the  top  of  the  plates 
and  at  the  proper  specific  gravity.    Use  only  pure  water  to  replace  evapora- 
tion.   In  preparing  the  electrolyte  never  pour  water  into  the  acid. 

9.  Keep  the  cells  free  from  dirt  and  all  foreign  substances,  both  solid 
and  liquid. 

_  10.  Keep  the  battery  and  all  connections  clean;  keep  all  bolted  connec- 
tions tight. 

11.  If  there  be  lack  of  capacity  in  a  battery,  due  to  low  cells,  do  not 
delay  in  locating  and  bringing  them  back  to  condition. 

12.  Do  not  allow  sediment  to  get  up  to  the  plates. 

Mercury  Arc  Rectifier. — This  is  a  device  for  obtaining  direct 
current  from  alternating  for  use  in  charging  storage  batteries. 
This  transformation  of  current  is  obtained  at  a  low  cost,  because 
the  regulation  is  obtained  from  the  alternating  side  of  the  rectifier, 
while  the  current  comes  from  the  direct  current  side. 

The  theory  is  as  follows :  In  an  exhausted  tube  having  one  or 
more  mercury  electrodes,  ionized  vapor  is  supplied  by  the  nega- 
tive electrode  or  cathode,  when  the  latter  is  in  a  state  of  "excita- 
tion." This  condition  of  excitation  can  be  kept  up  only  as  long 
as  there  is  current  flowing  towards  the  negative  electrode. 

If  the  direction  of  the  voltage  be  reversed,  so  that  the  formerly 
negative  electrode  is  now  positive,  the  current  ceases  to  flow,  since 
in  order  to  flow  in  the  opposite  direction  it  would  require  the 
formation  of  a  new  negative  electrode,  which  can  be  accomplished 


594  SELF-PROPELLED   VEHICLES. 

only  by  special  means.  Therefore,  the  current  is  always  flowing 
towards  one  electrode,  the  cathode,  which  is  kept  excited  by  the 
current  itself.  Such  a  tube  would  cease  to  operate  on  alternating 
current  voltage  after  half  a  cycle  if  some  means  were  not  pro- 
vided to  maintain  a  flow  of  current  continuously  towards  the 
negative  electrode. 

The  construction  and  operation  of  the  General  Electric  Com- 
pany's rectifier  is  as  follows : 

There  are  two  graphite  electrodes   (anodes),  and  one  mercury  cathode. 

Each  anode  is  connected  to  a  separate  side  of  the  alternating  current 
supply  and  also  through  reactances  to  one  side  of  the  load. 

The  cathode  is  connected  to  the  other  side  of  the  load.  As  the  current 
alternates  first  one  anode  and  then  the  other  becomes  positive  and  there 
is  a  continuous  flow  of  current  towards  the  cathode,  thence  through  the 
load  and  back  to  the  opposite  side  of  the  supply  through  a  reactance. 

At  each  reversal  the  reactances  discharge,  thus  maintaining  the  arc 
until  the  voltage  reaches  the  value  required  to  maintain  the  current  against 
the  counter  electromotive  force  of  the  load,  and  also  reducing  the  fluctua- 
tions in  the  direct  current.  In  this  way  a  true  continuous  current  is 
produced  with  very  small  loss  in  transformation. 

A  small  electrode,  connected  to  one  side  of  the  alternating  current 
circuit  is  used  for  starting  the  arc. 

A  slight  tilting  of  the  tube  makes  a  mercury  bridge  between  the  mer- 
cury cathode  and  the  small  electrode  and  draws  an  arc  as  soon  as  the  tube 
returns  to  a  vertical  position. 


CHAPTER    FORTY-FOUR. 

METHODS      OF     CIRCUIT-CHANGING     IN     ELECTRICAL     MOTOR 
VEHICLES,     AND    THEIR    OPERATION. 

Varying   the   Speed   and   Power  Output  of  a  flotor. — The 

methods  employed  to  vary  the  speed  and  power  output  of  an 
electric  vehicle  motor  consist  briefly  in  such  variation  of  the 
electric  circuits  as  will  modify  the  pressure  of  the  batteries  on 
the  one  hand  and  the  operative  efficiency  of  the  motors  on  the 
other.  This  is  a  very  simple  matter  and  may  be  expressed  in 
a  few  words.  As  is  well  known,  there  are  two  general  methods 
of  connecting  up  both  electric  batteries  of  any  description  and 
electric  motors.  They  are  the  series-wiring  and  the  multiple- 
wiring,  or  parallel-wiring.  In  series-wiring,  various  cells  of  a 
galvanic  battery,  or  the  several  units  of  a  battery  of  dynamos, 
are  connected  in  line.  At  one  terminal  of  each  is  the  negative 
pole,  at  the  other  the  positive — each  unit  in  combination  having 
its  negative  pole  connected  to  the  positive  pole  of  the  one  next 
following.  In  the  parallel  method  of  wiring  the  various  units 
are  each  separately  connected  at  their  positive  and  negative  poles 
to  two  lead  wires,  one  of  which  is  the  positive  pole  of  the  battery, 
the  other  the  negative. 

Effects  Obtained  by  Varying  the  Circuits.— Electric  motors, 
lights  and  other  electrically  effected  devices  are  similarly  con- 
nected in  circuits,  either  in  series  or  parallel.  Now,  in  the  mat- 
ter of  circuit  arrangements  on  this  plan,  one  general  principle 
may  be  laid  down,  which  is  that  a  connection  of  a  number  of 
electrical  generators  in  series  involves  an  increase  in  the  power 
pressure  of  the  battery,  which  is  equal  to  the  sum  of  the  individual 
voltages.  Connecting  a  number  of  generating  units  in  parallel 
or  multiple  has  the  effect  of  producing  a  pressure  only  equal  to 
the  voltage  of  one  of  the  units.  Thus,  if  four  generators  of  10 
volts  each  be  connected  in  series,  the  pressure  is  equal  to  40 
volts.  If,  however,  they  be  connected  in  parallel  or  multiple, 
the  pressure  is  equivalent  to  but  10  volts,  the  effect  in  the  latter 
case  being  the  same  as  if  but  one  unit  were  in  circuit,  so  far  as 

.595 


596 


SELF -PRO  FELLED  VEHICLES. 


the  voltage  is  concerned.  On  the  other  hand,  where  four  motors 
are  connected  in  series  the  efficient  pressure  of  the  circuit  is 
reduced  to  very  nearly  £  for  each  motor,  the  C.  E.  M.  F.,  gen- 
erated by  their  operation,  serving  to  cut  down  the  average  of 
efficiency ;  but  when  four  motors  are  connected  in  parallel,  which 
is  to  say,  bridged  between  the  limbs  of  the  circuit,  the  greatest 
available  pressure  of  the  battery  is  able  to  act  upon  each  one 
of  them. 


FIG,  43  9<— Diagram  of  the  Controlling  Apparatus  of  a  Columbia  Light  Electric 
Vehicle.  A,  brake  pedal ;  B,  ratchet  retaining  pedal  in  place,  operated  by  left 
foot;  C,  dash  board  ;  D,  body  sill ;  E,  steering  handle ;  F,  controller  handle ;  G, 
rocker  shaft  for  setting  hub  Drakes ;  J,  brake  oand  on  wheel  hub ;  H,  rear  axle. 

Arrangement  of  the    Batteries  and  Motor   Parts. — In    an 

electric  vehicle  the  storage  batteries  are  arranged  so  as  to  form 
a  number  of  units,  the  circuit  wiring  being  so  arranged  that  by 
the  use  of  a  form  of  switch  known  as  a  controller  the  connec- 
tions may  be  varied  from  series  to  multiple,  or  the  reverse,  as 
desired.  The  same  arrangement  for  varying  the  circuit  con- 
nections is  used  for  the  field  windings,  and,  with  some  manufac- 
turers, for  the  brush  connections  also.  In  the  accompanying 
first  diagram  of  the  connections  of  an  electric  vehicle  this  fact 
is  indicated.  The  dotted  lines  on  each  figure  indicate  the  cir- 


METHODS    OF    CIRCUIT-CHANGING. 


597 


cuiU  that  are  cut  out,  or  open,  and  the  full  lines  those  that  are 
active,  or  closed.  In  fig".  440  showing  the  first  speed,  we  have 
the  two  units  of  the  battery,  B,  connected  in  multiple,  which 
means  that  the  voltage  is  reduced  to  the  lowest  point.  The 
wire,  C,  connected  to  the  bridge  between  the  positive  poles  of 
the  battery,  leads  the  current  to  the  field  windings,  H  and  /, 
which,  in  this  figure,  are  connected  in  series-multiple,  which 


3V  SPEED 


fWlflfK 

W/wi 


FIG.  440.— Diagram  of  the  Circuit-Changing  Arrangements  of  a  Typical  Electrical 
Venicle.  The  full  lines  in  these  plans  indicate  the  closed,  or  active,  circuits;  the 
dotted  lines  the  open,  or  inactive,  circuits.  As  may  be  readily  understood,  the  whole 
scheme  of  circuit-changing  depends  on  employing  several  different  circuit  con- 
nections between  batterv  and  motor,  which  may  be  opened  and  closed,  as  desired. 
Here  A  and  C  are  the  lead  wires  between  battery,  B,  and  motor  brushes,  F  F  and 
G  G,  and  the  field-windings,  H  and  J,  and  wire,  D. 

gives  the  lowest  speed  and  power  efficiency  of  the  motors.  By 
the  wire,  D,  the  current  is  carried  to  the  brushes,  FF  and  GG, 
which,  according  to  this  scheme,  are  permanently  connected  in 
multiple,  the  return  path  to  the  negative  pole  of  the  battery  be- 
ing through  the  wire,  A. 


598  SELF-PROPELLED   VEHICLES., 

In  the  second  figure  of  the  diagram  the  circuit  is  varied  so  as 
to  connect  the  two  units  of  the  batteries,  so  as  to  give  its  highest 
pressure  efficiency.  But,  since  the  field  windings  of  the  motors 
are  also  connected  in  series,  or  in  series-parallel,  as  in  this  case, 
the  efficiency  in  speed  and  power  is  reduced  nearly  one-half. 

In  the  third  figure  the  two  units  of  the  battery  are  connected 
in  series,  which,  as  in  the  former  case,  indicates  the  greatest 
efficiency  in  power  output ;  but  the  field  windings  are  connected 
in  parallel,  which  means  that  the  C.  E.  M.  F.,  generated  by  their 
operation,  is  equivalent  to  the  C.  E.  M.  F.  of  only  one  motor, 
with  the  result  that  the  speed  and  power  efficiency  is  raised  to 
its  highest  point. 

Diagram  of  Battery,  flotor  and  Controller. — In  the  second 
diagram,  illustrating  a  typical  method  of  shifting  the  circuits, 
we  have  the  same  general  scheme  applied,  so  far  as  the  first, 
second  and  fourth  speeds  are  concerned,  the  connections  of  the 
controller  being  laid  out  in  rectangular  form  between  the  broken 
lines.  When  the  controller  is  rotated,  so  that  the  row  of  ter- 
minal points,  A,  B,  C,  D,  E,  F,  G,  are  brought  into  electrical 
contact  with  the  row  of  terminal  points,  on  the  controller,  A' ' ,  B', 
C',  D',  E',  F',  G',  we  have  the  first  speed  forward,  which,  as  may 
be  readily  discovered  by  tracing  the  connections  throughout,  in- 
volves that  the  two-unit  battery  is  connected  into  multiple  and 
the  field  windings  of  the  two  motors  in  series.  Tracing  the  con- 
nections indicated  for  the  second  speed,  we  see  that  the  terminal 
points,  A,  B,  C,  etc.,  are  brought  into  electrical  contact  with 
A*,  B',  C2,  etc.,  and  we  have  the  batteries  in  multiple  and  the 
fields  in  series-multiple.  Tracing  the  connections  indicated  for 
the  third  speed,  we  have  the  terminal  points,  B  and  C,  con- 
nected to  the  terminal  points,  B*  and  C3,  and  the  terminal  points, 
E  and  F,  connected  to  the  terminal  points,  E*  and  F3,  which 
means  that  the  batteries  are  connected  in  series  and  the  fields 
in  series.  Similarly,  by  tracing  the  connections  for  the  fourth 
speed,  we  find  the  terminal  points,  B  and  C,  connected  to  ter- 
minal points,  B*  and  C*,  and  the  terminal  points,  D,  E,  F,  G,  in 
electrical  connection  with  the  terminal  points,  D*,  E*,  F4,  G4, 
which  means  that  the  batteries  are  in  series  and  the  fields  in 
multiple.  The  connections  between  the  battery,  the  armature 
brushes  and  the  motor  fields,  are  made  as  indicated  through  the 


METHODS    OF    CIRCUIT-CHANGING. 


599 


Fio  44 L— Diagram  Plan  of  the  Several  Parts  of  an  Electric  Vehicle  Driving  Circuit. 
The  field-windings  and  armatures  are  shown  projected,  the  proper  wiring  connec- 
tions being  indicated.  The  periphery  of  the  controller  is  laid  out  within  the  broken 
line  rectangle,  the  contacts  and  connections  through  it  for  varying  the  circuits 
through  four  speeds  being  shown.  A,  B,  C,  D,  E,  F,  G  are  the  terminal  contact  points 
of  the"various  speed  circuits,  to  be  made  as  the  positions  of  the  controller  contacts 
are  varied.  A',  B',  C',  D',  E',  F'  are  the  controller  contacts,  which,  with  those 
already  mentioned,  make  the  proper  circuits  for  the  first  speed.  Similarly,  A",  B*, 
C*  etc  when  brought  into  contact  with  A,  B,  C,  etc.,  give  the  second  speed  circuits; 
33  C»  E',  F3,  in  contact  with  A,  B,  C,  D,  etc.,  give  the  third  speed;  and  B*,  C*,  D«, 
in  the  same  manner,  the  fourth  speed.  The  reverse  switch  gives  the  backward  move- 
ment, as  described. 


600 


SELF-PROPELLED    VEHICLES. 


rotary  reversing  switch,  by  the  terminals,  K,  L,  M,  N.  This 
switch  may  effect  the  reversal  of  the  motors  by  giving  a  quarter 
turn  to  its  spindle,  which  means  that  the  contacts  of  segment,  X, 
will  be  shifted  from  L  and  K  to  K  and  N,  and  the  contacts  of 
segment,  Y,  shifted  from  M  and  N  to  L  and  M,  thus  reversing 
the  direction  of  the  current. 

Electric  Vehicle  Company's  Circuits. — Some  leading  manu- 
facturers of  electric  vehicles,  notably  the  Electric  Vehicle  Co., 


FIG.  442,— Diagram  of  a  Typical  One-Battery-TJnit,  Two-Motor  Circuit.  The  first  speed 
shows  the  two  motors  in  aeries,  with  a  resistance  coil  interposed;  the  second,  the 
motors  in  series,  without  the  resistance;  the  third,  the  motors  in  multiple. 

vary  the  scheme  shown  in  the  last  two  figures  by  connecting  the 
armature  brushes  and  fields  of  each  motor  into  series,  and  shift- 
ing the  circuit  connections,  where  two  motors  are  used,  from 
series  to  series-parallel.  In  the  figure  showing  the  combination 
of  one  battery  unit  with  two  motors,  the  connections  for  the  three 
speeds  obtained  are  obvious.  Since  only  one  unit  is  used,  the 
lowest  pressure  of  the  battery  can  be  obtained  only  by  inserting 
a  resistance  coil,  R,  in  the  circuit,  with  the  armature  brushes, 


METHODS    OF    CIRCUIT-CHANGING. 


601 


rield  windings  and  both  motors  connected  in  series.  For  the 
second  speed  the  resistance  is  simply  cut  out,  allowing  the  full 
current  of  the  battery  to  pass  through  the  armatures  and  wind- 
ings of  both  motors,  still  connected  in  series.  For  the  third 
speed  the  connections  of  armatures  and  motors  are  shifted  to 
multiple,  or  series-multiple.  With  the  use  of  a  two-unit  bat- 


SPEED 


**  SPEED 


-lllllllll — II I 


J*P-  SPEED 


H|l|l|l|lHI'|l|l|l[) 


connections.    For  tne  tlrst  speed  the  battery  units  are  in  imuciptv;  lor  me  seconc 
in  aeries-multiple;  for  the  third,  in  aeries.   'The  motor  connections  are  not  varied. 

tery  and  two  motors,  it  is  possible  to  eliminate  the  resistance 
coil  altogether  and  depend  entirely  upon  circuit  shifting  regulat- 
ing the  voltage  and  power.  Accordingly,  for  the  first  speed  we 
have  the  batteries  connected  in  multiple,  and  the  armatures  and 
windings  of  the  two  motors  in  series.  For  the  second  speed, 


GQ3 


SELF -PRO  POLLED  VEHICLES. 


the  series  connections  are  adopted  for  both  batteries  and  motors, 
while  for  the  third  speed  the  batteries  are  in  series,  with  the 
motors  in  parallel. 

A  Four-Battery-Unit,  One-Hotor  Circuit. — In  the  diagram  in- 
dicating the  use  of  four-battery-units  with  one  motor,  which,  as 
shown  in  an  accompanying  cut,  is  used  to  drive  both  rear  wheels 
of  the  wagon  through  a  single  reduction,  it  is  possible  to  obtain 


3<if  SPEED 


FIG.  444,-Diagramof  a  Two-Battery-Unit,  Two-Motor  Circuit,  showing  combinations  for 
three  speeds.  The  first  speed  is  obtained  with  the  battery  units  in  multiple,  and  the 
motors  in  series;  the  second,  with  the  battery  units  in  series,  and  the  motors  in 
series;  the  third,  with  the  battery  units  in  series,  and  the  motors  in  multiple. 

a  still  greater  range  of  variation  by  the  simple  shifting  of  the  bat- 
tery circuits,  without  alteration  of  the  armature  or  field  connec- 
tions. Accordingly,  for  the  first  speed  we  have  the  four  units 
connected  into  parallel,  which  gives  a  total  voltage  equivalent  to 
the  voltage  of  any  one  of  them.  For  the  second  speed,  the  bat- 
tery units  are  connected  into  series,  the  two  pairs  thus  formed 
being  joined  in  multiple,  with  the  result  that  the  total  voltage  of 
the  battery  is  equivalent  to  the  sum  of  the  voltage  of  two  of  the 


METHODS  OF  CIRCUIT  CHANGING. 


603 


units,  or  twice  the  voltage  used  in  the  first  speed.  For  the  third 
speed,  all  four  units  of  the  battery  are  connected  into  series,  thus 
doubling  the  voltage  again,  and  realizing  the  highest  speed  and 
power  efficiency  possible  in  the  combination. 

Vehicle  Circuit  Arrangements. — The  next  two  figures  illus- 
trate different  methods  of  arranging  the  circuits  of  an  electric 

D D  OD  DHZhCj 

Q [] 

CHU         OD  DCJ 


FIG.  445.— Diagram    of    Controller    Connections    of    a    One-unit,   One-motor 
Circuit,  with  Variable  Fields. 

vehicle  in  actual  practice.  In  the  first,  which  shows  the  arrange- 
ments used  on  light  Waverley  carriages,  the  one-unit  battery  in 
three  trays  is  shown  connected  in  an  invariable  series  circuit, 
giving  the  first,  or  lowest,  speed  through  the  resistance  coil  be- 
tween controller  contacts,  i  and  2,  the  motor-fields  being  in 
series;  the  second  speed  with  the  same  circuit  without  the  re- 


604 


SELF-PROPELLED   VEHICLES. 


CAaty* 


i?  a  «i 


ea<f. 


tiea.et- 


i  n 


''"speed  back- 


QD  D 


FIG.  446.— Diagram  of  Controller  Connections  of  a  Four-unit,  One-motor, 
Circuit,  with  Constant  Series  Connections  for  Fields  and  Armature  in 
Forward  and  Backward  Speeds. 


METHODS   OF   CIRCUIT   CHANGING.  605 

sistance,  and  the  third  speed  with  the  motor-fields  in  parallel. 
The  motor  used  on  these  carriages  is  of  the  six-pole  type,  the 
field  coils  being  divided  into  two  halves  of  three  coils  each,  each 
half  being  independently  connected  to  the  controller  contacts,  as 
shown  in  the  cut.  Reversal  is  by  a  form  of  rotatable  switch, 
and  an  electric  brake  is  also  used,  which  operates  on  the  princi- 
ple of  reversing  the  polarity  between  the  armature  and  field 
windings.  In  the  second  diagram  is  shown  the  connections  of  a 
series  motor,  in  which  the  field  and  armature  windings  are  in 
invariable  series  connections  for  all  forward  speeds.  The  first, 
or  lowest,  speed  forward  is  obtained  with  three  units  of  the  bat- 


FIG.  447.— A  Typical  Electrical  Vehicle  Controller,  or  Circuit-changing 
Switch.  The  circuit  terminals  of  battery  and  motors  are  shown  at  the 
jack-springs,  which  are  arranged  to  be  engaged  by  the  fins  on  the  per- 
iphery of  the  controller-cylinder.  The  connections  within  the  controller, 
between  the  fins,  are  the  same  as  those  shown  in  Fig.  446.  except  for 
the  fact  that  the  four  rings  at  the  right  hand  end  provide  constant  volt- 
age connections  for  use  with  a  shunt  motor.  The  gaps  at  the  rear  of  the 
rings  show  means  for  cutting  out  the  shunt  field  at  top  speed. 

tery  in  series-multiple ;  the  second,  with  the  four  units  in  series- 
multiple;  the  third,  with  the  four  units  in  series.  In  reversing, 
the  first  and  second  speeds  backward  correspond  to  the  for- 
ward speed  arrangements  similarly  numbered,  with  the  excep- 
tion that  the  connections  of  field  and  armature  are  reversed,  as 
may  be  readily  understood  from  following  out  the  indicated 
connections.  In  the  charging  position,  the  three  contacts  at  the 
right  side  of  the  controller  are  cut  out,  leaving  the  battery  to 
be  charged  in  series  from  the  charging  plug  connections  to  con- 
tact, A,  at  the  left  of  the  controller,  to  the  similar  connections 
with  the  negative  pole  of  battery,  4. 


306  SELF-PROPELLED   VEHICLES. 

The  Controller  of  an  Electric  Vehicle. — The  controller  of 
an  electric  vehicle  consists  of  a  rotatable  insulated  cylinder,  car- 
rying on  its  circumference  a  number  of  contacts,  arranged  to 
make  the  desired  connections  with  the  terminals  of  the  various 
apparatus  in  the  circuit  through  a  wide  range  of  variation.  As 
shown  in  fig-.  441,  illustrating-  the  arrangement  of  battery  and  con- 
trollers in  an  electric  vehicle,  it  should  be  noted  that  for  the 


FIG.  448. — Controller  of  the  Rauch  and  Lang  electric  vehicles.  It  is  of  the  flat  radial  type. 
Two  movable  copper  leaf  contacts  of  ample  size  make  all  commutations  necessary  to 
obtain  the  various  speeds.  Five  speeds  forward  and  revc  rse  are  provided.  All  speeds 
being  obtained  on  the  same  voltage  permits  a  constant  to -quo  working  where  at  no 
speed,  from  the  loweit  to  the  highest,  is  the  circuit  open  for  an  instant,  and  the  motor 
is  doing  work  at  every  position  of  the  controller  handle. 

first  speed,  in  which  the  batteries  are  connected  in  multi- 
ple, the  points,  A',  C',  are  in  electrical  connection,  as  indicated 
by  the  lines  between  them,  so  that  the  points,  A,  C,  connected  to 
the  like  poles  of  the  two  battery  units,  are  directly  connected, 
thus  bringing  the  two  units  into  multiple.  The  battery  circuit 
is  completed  by  the  electrical  connection  on  the  controller  be- 
tween the  points,  B'  and  D' ' ,  when  they  are  brought  into  contact 
with  the  points,  B  and  D,  which  connect  to  the  two  other  poles 
of  the  battery.  Furthermore,  the  points,  H'  and  F',  being  in 
electrical  connection  through  the  body  of  the  controller,  connect 
points,  H  and  F,  direct,  thus  throwing  the  field  windings  of  the 


METHODS  OF  CIRCUIT  CHANGING. 


607 


motors  into  series.  As  may  be  understood  from  the  last  two 
diagrams  of  vehicle  circuits,  the  contacts  may  be  arranged  to 
make  any  of  several  schemes  of  circuit  variation,  although,  as 
must  be  obvious  on  examination,  a  specially  arranged  controller 
is  necessary  for  each  separate  scheme. 

Construction  of  a  Controller. — The  accompanying  cuts  show 
the  general  appearance  and  construction  of  several  types  of  con- 
troller for  electrical  vehicles.  As  may  be  seen  in  the  first  cut, 


FIG.   449.— Chassis  of  a  Heavy  Wagon  of  the  Electric  Vehicle    Co.,   showing 
arrangement  of  controlling  apparatus. 

the  connections  of  the  terminals  of  the  batteries,  of  the  field 
windings,  and  other  elements  of  the  circuit,  are  made  at  the 
binding  posts  at  the  front  base  of  the  instrument.  From  each 
of  these  binding  posts,  which  are  electrically  insulated  from  one 
another,  jack-springs  rise  to  a  position  convenient  to  make  con- 
nections with  the  switch  blades  arranged  along  the  periphery  of 
the  controller  cylinder.  These  switch  blades,  as  may  be  seen, 
are  secured  to  the  controller  cylinder  by  screw  connections,  be- 


608  SELF-PROPELLED    VEHICLES. 

ing  arranged  singly,  or  several  of  them  together  on  one  plate. 
In  the  case  of  a  pair  of  blades,  shown  in  contact  with  the  spring 
at  either  extremity  of  the  controller  cylinder,  it  is  evident  that 
there  is  an  electrical  contact,  through  the  base  plates,  between 
the  two  terminals,  represented  by  the  contact  springs  in  engage- 
ment. Between  these  two  end  plates,  as  may  be  seen,  there, 
are  several  switch  blades  arranged  singly  upon  the  circumfer- 
ence. At  one  point  there  is  no  contact  whatever,  showing  that 
the  terminals  represented  by  the  contact  springs  at  that  point  are 
out  of  circuit.  These  several  blades  that  are  arranged  singly  on 
the  controller  surface  have  such  electrical  connections  as  the 
scheme  of  circuit  variation  adopted  demands,  made  through  in- 
sulated wire  connections  arranged  between  any  pair  it  is  desired 
to  connect.  This  is  the  arrangement  indicated  in  the  diagram 
of  connections  already  described.  It  is  perfectly  easy  to  under- 
stand, therefore,  how  the  circuit  arrangements  of  battery  units 
and  motor  windings  may  be  varied  through  any  desired  range 
of  connections,  by  simply  connecting  their  terminals  through 
properly  arranged  and  connected  controller  contacts. 

Varieties  of  Controller. — The  controller  shown  in  the  cut, 
already  described,  represents  only  one  type  of  this  machine. 
Some  controllers  are  constructed  simple,  with  a  perfectly  cylin- 
drical surface,  upon  which  bear  single  leaf  springs,  the  desired 
electrical  connections  being  made  by  suitably  connected  conduct- 
ing surfaces  on  the  cylinder  circumference,  and  cut-outs  being 
similarly  accomplished  by  insulating  surfaces,  bearing  against 
the  spring  contacts  at  the  desired  points.  This  type  of  control- 
ler is  shown  in  the  second  cut,  and  is  one  of  the  most  usual 
forms  for  motor  vehicle  purposes.  As  is  perfectly  obvious,  it  is 
possible  to  so  arrange  the  electrical  connections  on  the  controller 
surfaces,  that  by  proper  contacts  with  the  terminal  springs,  re- 
versal of  the  motor  may  be  accomplished,  as  shown  on  the  last 
circuit  diagram.  This  is  done  in  a  number  of  controllers,  the 
reverse  being  accomplished  at  a  definite  notch  on  the  quadrant 
of  the  shifting  lever. 


CHAPTER  FORTY-FIVE. 

AUTOMOBILE  RUNNING,  CARS  AND  REPAIR. 

Introductory. — In  the  handling  of  a  car  on  the  road,  it  would 
be  hard  to  find  two  drivers  who  would  adopt  the  same  methods. 
This  is  due  to  the  varied  experience  the  drivers  have  had,  and  to 
their  knowledge  of  the  theory  and  principles  of  the  automobile. 
Under  suitable  conditions,  the  gas  engine  will  run  for  a  long  time 
without  attention.  However,  a  slight  fault  will  often  cause  con- 
siderable trouble,  the  symptoms  of  which  may  not  be  plain  enough 
to  enable  the  trouble  to  be  located  directly,  and  the  whole  system 
must  be  gone  over  sometimes  before  it  is  located.  It  is,  therefore, 
necessary  to  know  just  what  is  happening  under  the  bonnet,  and 
just  when  some  things  should  happen,  that  reasonable  satisfaction 
may  be  derived  from  the  car. 

There  is  no  car  that  can  be  expected  to  be  free  from  trouble, 
for  even  the  best  workmanship  and  material  may  give  way  some- 
times. 

An  inexperienced  driver  will  find  that  he  cannot  get  as  much 
out  of  a  car  as  the  demonstrator  for  some  little  time,  or  till  he  is 
thoroughly  accustomed  to  the  car  and  knows  how  to  handle  it, 
whether  traveling  uphill  or  on  the  level. 

To  handle  a  car  intelligently,  the  driver  should,  I,  be  well 
acquainted  with  the  carburetter  and  ignition  system,  2,  under- 
stand the  management  of  the  spark,  throttle  and  control  levers 
under  varying  road  conditions,  3,  give  proper  attention  to  the 
lubrication  of  the  various  parts,  and  4,  be  able  to  make  repairs  re- 
sulting from  the  ordinary  mishaps  likely  to  be  encountered  on  the 
road. 

The  control  of  a  steamer  or  electric  vehicle  is  not  so  complicated,  but 
the  driver  should  have  a  good  knowledge  of  the  principles  of  operation 
of  the  motive  power  in  either  case  and  understand  any  peculiarities  that 
may  be  inherent  in  the  system. 

609 


610          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

Before  Starting  the  Car. — In  the  chapter  on  engine  operation, 
detailed  instructions  are  given  for  its  management  and  care, 
hence,  it  will  suffice  to  say  little  here  on  this  phase  of  the  sub- 
ject. 

Before  taking  a  car  out  on  the  road,  the  driver  should  first 
make  himself  familiar  with  the  instructions  given  in  the  above 


EMERGENCY  BRAKE 
LEVER 


CIRCULATION  GAUGE 


OR  STARTING  PLUG 


FIG.  450. — Control  levers  and  dashboard  appliances  on  a  gasoline  automobile.  Located 
at  the  side  of  the  car  are  the  two  levers  which  operate  the  brake  and  shift  the  change 
speed  gears.  As  shown,  the  throttle  and  spark  levers  are  just  below  the  steering 
wheel;  a  number  of  cars  have  the  levers  placed  on  top  of  the  wheel.  The  arrangement 
of  foot  pedals  illustrated  in  the  figure  is  to  be  found  on  nearly  all  makes  of  cars. 

mentioned  chapter   and   also   with  the  "control"   system   which 
will  now  be  explained. 

Control. — The  term  "control,"  relates  to  the  various  levers  and 
devices  used  in  running  the  car  and  which  are  conveniently  located 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          611 

on  the  dash,  steering  column  and  foot  board.  A  typical  arrange- 
ment is  shown  in  fig.  450.  They  are  marked  in  the  figure  and 
their  location  should  be  carefully  noted. 

The  Throttle  Levers. — It  will  be  seen  that  there  are  two 
throttle  levers,  most  cars  being  provided  with  this  number.  In 
running  a  car  through  crowded  streets  where  frequent  speed 
changes  are  to  be  made,  this  is  done  most  conveniently  with  the 


FIG.  451. — The  Holsman  high-wheeled  gasoline  surrey.  This  vehicle  is  fitted  with  either 
a  two  or  four-cylinds  •  engine,  developing  respectively  12J  and  26  horsepower.  The 
transmission  for  both  ow  and  high  speed  is  direct  from  the  motor  shaft  to  the  wheels 
through  a  steel  frictio  i  chain.  One  control  lever  of  rack  and  pinion  type  operates  the 
high  and  low  gear  and  reverse.  The  vehicle  starts  and  runs  on  all  ordinary  roada 
from  zero  to  twenty-five  or  thirty  miles  per  hour  by  friction  of  the  steel  chains  operat- 
ing on  grooved  sheaves  on  the  ends  of  the  motor  shaft  to  the  sheaves  on  both  rear 
wheels.  The  reverse  s  accomplished  by  pushing  the  grooved  pulleys  on  the  ends  of 
the  motor  shaft  back  into  engagement  with  the  steel  channels  or  rims  of  the  wheels, 
by  the  same  control  'ever.  The  driving  chains  are  wholly  and  automatically  raised 
from  engagement  whenever  the  tension  on  them  is  relieved  or  the  brake  is  set,  or 
whenever  the  reverse  .s  hi  action. 

foot.  A  downward  pressure  of  the  foot  opens  the  throttle;  it 
closes  automatically  when  released  by  the  action  of  a  spring.  The 
foot  throttle  is  also  used  when  shifting  the  transmission  gears, 
as  one  hand  is  required  to  operate  the  gear  shifting  lever,  while 
the  other  is  engaged  in  steering  the  car. 


612          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

The  running  conditions  on  an  open  or  country  road  are  such 
that  the  hand  throttle  lever  may  be  used  to  advantage  since  it 
need  not  be  moved  so  often.  The  hand  throttle  may  be  set  at 
any  desired  opening  and  it  will  remain  in  any  position,  whereas 
if  the  foot  throttle  be  used,  it  is  necessary  to  retain  it  in  position 
by  the  foot  against  the  tension  of  the  spring.  The  latter  opera- 
tion naturally  becomes  tiresome  if  continued  for  any  length  of 
time,  hence,  the  hand  throttle  furnishes  a  ready  relief. 

Each  throttle  is  arranged  so  that  when  the  lever  is  in  the  closed 
position,  the  supply  of  fuel  mixture  to  the  engine  is  not  entirely 
shut  off  but  just  sufficient  to  keep  the  engine  in  motion. 

As  shown  in  the  illustration,  the  throttle  lever  is  placed  below  the 
steering  wheel,  however,  in  many  cars  it  is  placed  above  the  wheel.  A 
notched  segment  is  provided  to  retain  the  throttle  in  any  setting. 

The  Spark  Control  Lever. — This  is  usually  placed  near  the 
throttle  lever  where  it  can  be  conveniently  operated  while  steer- 
ing. Both  the  spark  and  throttle  are  placed  either  below  or  above 
the  steering  wheel.  The  latter  arrangement  seems  most  in  favor 
as  the  two  levers  can  be  operated  without  removing  the  hands 
from  the  rim  of  the  steering  wheel. 

The  Brake  Levers. — When  two  sets  of  brakes  are  provided  it 
is  usual  to  have  one  set  controlled  by  the  foot  brake  pedal  and 
another  by  the  emergency  lever. 

The  running  or  service  brake,  is  operated  by  the  foot  pedal 
and  is  released  by  a  spring  when  not  held  down.  The  construc- 
tion is  such  that  when  this  pedal  is  depressed  to  apply  the  brake, 
the  clutch  is  simultaneously  released.  This  arrangement  prevents 
an  inexperienced  or  confused  driver,  applying  the  brake  without 
releasing  the  clutch — a  proceeding  which  would  strain  or  bring 
heavy  stresses  on  the  engine  and  driving  gear. 

Sometimes  the  emergency  brake  is  arranged  to  simultaneously  release 
the  clutch  when  applied,  but  this  construction  has  been  criticised  by  some 
authorities  as  undesirable  in  handling  the  car  on  a  hill. 

It  is  pointed  out,  that  if  it  be  necessary  to  stop  the  car  in  ascending  a 
hill,  the  brakes  must  be  released  before  the  clutch  can  be  thrown  in,  with 
the  possibility  of  the  car  starting  down  hill  backward  before  the  power 
can  be  applied.  The  chance  of  stalling  the  engine  through  this  and  the 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          613 


.  452.— Plan  of  the  Brush  Runabout.  Parts  are  as  follows :  A,  priming  push  rod ; 
B,  cylinder  head;  C,  carburetter  gasoline  adjustment ;  D,  carburetter  fuel  cup  ;  E, 
removable  cap  over  exhaust  valve ;  F,  spark  plug  cap  over  inlet  valve ;  G,  gaso- 
line pulsation  pump;  H,  removable  plate  on  crank  case;  I,  starting  crank ; 
J,  muffler;  K,  gasoline  tank;  L,  steering  gear:  M,  differential  gear;  N,  trans- 
mission  case;  O,  interlocking  device;  P,  gear  and  clutch  lever;  Q,  brake  foot 
pedal;  R,  driving  sprocket;  S,  spring;  T,  radius  rod;  U,  adjustablo  friction 
joint  of  radius  rod. 


614          AUTOMOBILE  RUNNING,  CARS  AND  REPAIR. 

t 

danger  of  the  combination  to  any  but  an  experienced  driver,  it  is  con- 
tended, make  it  advisable  to  have  the  emergency  brake  separate  from  any 
connection  with  the  clutch. 

The  emergency  brake  lever  is  provided  with  a  pawl  and  notched 
segment  for  retaining  it  in  position  when  set.  This  segment  is 
concentric  with  the  segment  of  the  transmission  gear  shifting 
lever,  the  brake  lever  being  always  placed  outside.  On  some  cars 
the  segment  has  a  hole  drilled  to  receive  a  padlock.  When  the 


:HANGC  &M  urvwi 


Fra.  453. — Franklin  emergency  brake  and  transmission  levers,  as  applied  to  modete 
having  progressive  transmissions. 

lever  is  drawn  past  this  hole  and  padlock  inserted,  the  clutch  is 
out  and  the  brake  applied,  so  that  the  car  is.  protected  against 
unauthorized  use  or  theft. 

The  Clutch  Pedal. — The  usual  location  of  this  device  is  to  the 
left  on  the  floor  board  to  be  operated  by  the  left  foot.  By  press- 
ing down  this  pedal  the  clutch  is  released  which  allows  the  engine 
to  run  free  by  disconnecting  it  from  the  transmission. 

As  previously  mentioned,  there  is  a  connection  between  the  clutch  and 
brake  pedals,  such  that  if  the  latter  be  pressed  down  the  clutch  is  re- 
leased at  the  same  time  the  brake  is  applied  for  reasons  already  explained. 


AUTOMOBILE.  RUNNING,  CARE  AND  REPAIR. 


615 


There  is  a  simplified  arrangement  on  some  cars  in  which  a 
single  pedal  operates  both  clutch  and  brake.  Pressure  on  this 
pedal  fit  st  throws  out  the  clutch  while  continued  movement  of  the 
pedal  applies  the  brake.  This  arrangement  leaves  the  right  foot 
free  to  operate  the  foot  throttle. 

The  Transmission  Gear  Shifting  Lever. — This  lever  is 
located  beside  the  emergency  brake  lever  but  is  always  the  inner 


FIG..  454. — The  Maxwell  transmission  lever,  showing  the  several  positions  of  the  lever  in 
making  the  speed  changes.     The  transmission  is  of  the  progressive  type. 

one  or  that  one  nearest  the  driver.  On  most  cars  it  is  further 
distinguished  by  the  construction  as  is  shown  in  fig.  453,  the  brake 
lever  being  provided  with  an  external  latch  while  the  transmis- 
sion lever  has  a  press  button  on  top,  the  latch  link  passing  down 
through  the  handle. 

The  shape  of  this  segment  must  be  such  that  the  proper  move- 
ments may  be  given  to  the  lever  in  shifting  the  gears,  according 
to  the  type  of  transmission  used. 


616          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

When  the  car  is  fitted  with  a  progressive  transmission  a  simple 
linear  movement  of  the  lever  is  sufficient  to  affect  the  different 
gear  changes,  the  lever  being  rotated  through  the  proper  arc. 
This  type  of  transmission  control  as  applied  to  the  Maxwell  car, 
is  shown  in  fig.  454.  The  positions  for  the  different  speed  changes 
are  shown  by  the  dotted  lines,  the  latch  segment  having  notches 
in  the  proper  places  to  retain  the  lever  in  position. 

The  selective  type  of  transmission  requires,  instead  of  the  simple 
latch  segment,  a  compound  form  of  segment,  known  as  a  selector, 
since  with  selective  transmissions  it  is  necessary  in  shifting  the 
gears,  to  give  in  certain  cases  both  a  linear  and 
a  lateral  movement  to  the  lever.  A  selector  is 
simply  a  compound  segmental  guide  for  the 
transmission  lever,  having  two  slots  for  a  three 
speed  transmission,  three  slots  for  four  speed 
transmissions,  and  a  central  gate  to  provide  for 
the  necessary  lateral  movement  of  the  lever  in 
passing  from  one  slot  to  another.  Fig.  455  shows 
the  position  of  the  selector  with  respect  to  the 
lever.  The  brake  lever  is  also  shown  on  the  out- 
side, the  whole  forming  a  structural  unit  which 
is  attached  to  the  side  of  the  car.  In  shifting 
the  gears  for  the  several  speed  changes,  the  lever 
is  moved  to  the  various  slot  terminals,  the  central 
position  at  the  gate  corresponding  to  the  neutral 
position. 

There  seems  to  be  no  standard  arrangement 
of  the  slot  terminals  for  the  different  speeds.    A 

FIG.   455. — Character- 
istic side  lever  con-   great  diversity  exists,  as  is  shown  in  the  accom- 

trol.  The  two  levers    C  •* 

have  distinctive  con-    panying  CUtS. 
structions,  the  brake    *        * 
lever  having  an  ex- 
ternal latch  mechan- 
ism and  the  trans-       Figs.  456  to  461  are  examples  of  three  speed  selectors, 
mission  lever  being    an(j  figs>  ^2   to  ^  are  four  speed    selectors,   showing 

EuttonaMhe  topeof  the  varied  slot  arrangements  to  be  found  on  different 

the  handle  and  con-  makes  of  cars.     The  numerals  1,2,3  and  4  indicate  the 

nection     running  positiOn  of  the  lever  for  the  different  speeds  forward,  S 

through  same  to  the  P^  ^  ^^  fof 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


617 


FIGS.  456  to  461. — Types  of  three  speed  selectors  as  used  on  well-known  American  auto» 
mobiles  in  the  greatest  proportion.  Fig.  456,  Franklin ;  fig.  457,  Columbia  and 
Corbin;  fig.  458,  Apperson,  Cadillac,  Elmore,  Knox,  Oldsmobile,  Walter,  Winton  and 
Thomas;  fig.  459,  Buick  model  five;  fig.  460,  Locomobile;  fig.  461,  Thomas. 


PIGS.  462  to  463. — Types  of  four  speed  selectors  as  used  on  American  automobiles, 
showing  wide  variation;  fig.  462,  Lozier  model  G;  fig.  463,  Peerless  and  Stearns;  fig. 
464,  Studebaker;  fig.  465,  Lozier  model  H;  fig.  466.  Matheson;  fig.  467,  Toledo;  fig. 
468.  Simplex. 


618          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

The  Muffler  Cut  Out. — Since  the  action  of  a  muffler  tends  to 
increase  the  back  pressure  of  the  exhaust  and  thereby  diminish 
the  power  of  the  engine,  it  is  desirable,  in  running  over  heavy 
road  or  ascending  a  hill,  to  switch  out  the  muffler  and  allow  the 
engine  to  exhaust  directly  into  the  atmosphere,  that  its  full  power 
may  be  applied  in  propelling  the  car.  In  order  that  this  may  be 
conveniently  done,  a  cut  out  or  three-way  valve  is  connected  to 
the  exhaust  pipe  between  the  engine  and  muffler.  The  operation 
of  this  valve  is  controlled  by  a  press  button  placed  on  the  foot 
board  usually  located  conveniently  to  the  driver's  left  foot. 

Foot  Whistle  Control. — In  addition  to  the  usual  horn  signal, 
a  chime  whistle  is  sometimes  fitted  to  four  and  six  cylinder  cars. 

The  whistle  is  operated  by  the  exhaust  from  the  engine  and  produces 
a  pleasing  sound,  especially  on  a  six  cylinder  car,  the  rapid  variations 
of  the  exhaust  pressure  producing  a  trembling  tone. 

The  whistle  is  connected  to  the  exhaust  pipe  with  a  Tee,  and  its  valve 
operated  by  a  push  button  located  on  the  foot  board  near  the  muffler 
cut  out  button. 

Other  Dash  and  Foot  Board  Attachments. — In  addition  to 
the  various  levers  and  control  devices  already  described,  there  are 
other  attachments  that  are  placed  within  reach  of  the  driver. 

The  Coil  Box. — In  the  absence  of  a  high  tension  magneto,  an 
induction  coil  is  a  necessary  part  of  the  ignition  system,  and  this 
is  usually  located  on  the  dash  at  the  left  side.  With  synchronous 
ignition  the  coil  is  a  small  affair,  when  a  multi-unit  coil  is  used, 
its  casing  assumes  larger  proportions.  The  vibrators  being  placed 
at  the  top  are  conveniently  located  for  adjustment. 

Ignition  Cut  Out  Plug. — In  order  to  prevent  any  one  operat- 
ing the  car  without  the  owners  consent,  especially  when  left 
standing  in  a  public  place,  a  plug  switch  is  inserted  in  the  prim- 
ary circuit  of  the  ignition  system  and  located  on  the  dash  or 
some  other  convenient  yet  non-conspicuous  place,  so  that  the  plug 
is  easily  removed  by  the  driver  on  leaving  the  car. 

Self  Starter. — A  number  of  cars  are  now  fitted  with  self  start- 
ing devices,  thus  eliminating  cranking.  The  method  employed 
by  the  Winton  Company  on  their  six  cylinder  car  is  as  follows : 


AUTOMOBILE.  RUNNING,  CARE  AND  REPAIR. 


619 


Attached  to  cylinders  i  and  6  are  outlets  through  which  a  small  portion 
of  the  pressure  of  each  pov:er  stroke  passes  to  a  pressure  tank  placed 
between  the  left  frame  rail  and  the  driving  shaft.  Here  the  pressure  is 
stored  until  required  to  start  the  motor,  when  a  cock  is  opened,  allowing 
the  pressure  to  flow  through  the  distributor  to  one  of  the  cylinders.  The 
pressure  forces  this  piston  down,  and  at  the  same  time  another  piston 
passes  the  firing  point  and  the  motor  starts.  However,  if  for  any  reason 
the  first  cylinder  should  fail  to  fire,  the  distributor  sends  the  pressure  to 
the  cylinder  next  in  order,  and  forces  the  next  piston  past  the  firing 
point,  and  so  on,  if  necessary,  through  the  series  of  cylinders. 

The  control  of  the  self-starter  is  shown  in  fig.  469,  consisting  of  a  push 
button,  which  allows  pressure  to  flow  from  the  tank  to  the  cylinders. 
Immediately  above  the  press  button  is  the  pressure  gauge  which  indicates 
the  amount  of  pressure  in  the  tank.  In  addition,  there  is  a  shut  off  valve 


Fio.  469. — Winton  six  dash  assemblage,  showing  from  left  to  right,  the  auxiliary  gasoline 
tank,  the  shut  off,  push  button  and  gauge  of  self  starter,  the  spark  coil  and  oil 
sight  feed. 

for  use  when  the  car  is  to  remain  long  idle,  preventing  loss  of  pressure 
from  the  storage  tank.  The  other  devices  shown  in  the  dash  assemblage 
are;  i,  the  auxiliary  gasoline  tank  at  the  left,  2,  the  spark  coil,  and  3, 
the  oil  sight  feed. 


Starting  the  Car. — After  performing  the  preliminary  opera- 
tions, as  set  forth  in  Chapter  Thirty-three  the  driver  takes  his 
position  at  the  steering  wheel  and  is  ready  to  start  the  car.  These 
preliminary  operations  may  be  briefly  summarized  as  follows : 

{the  gasoline  tank  must  be  filled ; 
the  radiator  supplied  with  clean  water; 
the  lubricators  filled  and  bearings  oiled. 


620          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


2.  Before  Cranking  :•< 


the  brake  should  be  set,  which  releases 

clutch ; 
the  gasoline  valve  should  be  opened  and 

carburetter  primed ; 
the  spark  fully  retarded; 
the  throttle  placed  at  starting  position  or 

about  one-quarter  opening. 


fin  the  absence  of  a  self  starter,  the  operation  of 
p      .  .       J     cranking  the  engine  should  be  performed  with 
3.  ura     mg:<     care>  as  directed  in  Chapter  Thirty-three   to 
avoid  personal  injury. 

A  ,.,      r*      i  •        f  the  throttle  should  be  closed : 
4.  After  Cranking:  j  the  spark  advanced. 

Having  performed  the  above  operations,  the  driver  now  takes 
his  seat  and  starts  the  car  as  follows : 

1.  The  engine  speed  must  be  increased  by  slightly  retarding 
the  spark. 

The  throttle  and  spark  adjustments  made  immediately  after  cranking 
were  for  the  slowest  engine  speed,  just  sufficient  to  keep  it  turning  until 
the  driver  has  mounted  his  seat  and  is  ready  to  start  the  car. 

2.  Before  any  load  is  put  on  the  engine,  its  speed  must  be  in- 
creased in  order  to  store  up  in  the  fly  wheel  sufficient  momentum 
to  keep  it  going  between  power  strokes,  against  the  added  re- 
sistance of  the  load.    This  increased  speed,  as  stated,  is  secured 
by  spark  adjustment  rather  than  by  changing  the  throttle  posi- 
tion—  the  latter  method  being  reserved  for  any  additional  increase 
of  speed  that  may  be  necessary. 

3.  The  clutch  pedal  is  fully  depressed  and  held  down; 

4.  The  emergency  brake  released. 

It  should  be  remembered  that  the  emergency  brake  and  clutch  are  so 
connected  that  when  the  brake  is  set,  the  clutch  is  automatically  released, 
it  being  thrown  into  engagement  with  the  transmission  upon  the  release 
of  the  brake.  Hence  to  prevent  the  clutch  being  thrown  in,  when  the 
brake  is  released,  the  clutch  pedal  is  held  down  before  releasing  brake. 

5.  With  clutch  still  disengaged,  the  transmission  lever  is  moved 
to  first  speed  position. 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


621 


The  transmission   lever   is    assumed   to   be   in    its    neutral   position,   to 
which  position  it  should  always  be  brought  when  the  car  is  stopped. 

6.  The  right  foot  is  placed  on  the  throttle  pedal,  or  accelerator 
as  it  is  sometimes  called,  ready  to  press  down  and  increase  the 
throttle  opening  should  the  engine  show  any  tendency  to  diminish 
its  speed  or  stop. 

7.  The  clutch  pedal  should  then  be  slowly  released,  which  will 
allow  the  clutch  to  engage  gradually  and  start  the  car  easily  and 
without  jerk. 


FIG.  470. — The  American  Traveller  with  40  inch  wheels.  An  example  of  the  underslung 
frame  type  of  car.  Four  cylinder  engine,  bore  5j  in.;  stroke,  5i  in.,  50  H.  P.  Double 
ignition  system — Bosch  high  tension  magneto  and  single  unit  coiL 


To  Change  to  Second  Speed. — In  making  a  speed  change 
there  are  three  things  to  be  done  and  it  is  important  to  remember 
the  order  in  which  these  operations  should  be  performed,  viz. : 

1.  The  clutch  must  be  detached  by  pressing  down  on  the  clutch 
pedal  with  the  left  foot. 

2.  AFTER  WAITING  ONE  OR  Two  SECONDS,  in  order  that  the  two 
gears  to  be  meshed  shall  be  rcz'ok'ing  at  nearly  the  same  speed, 
quickly  move  the  transmission  lever  to  second  speed  position. 

During  the  wait,  the  speed  of  the  engine  may  be  accelerated  by  the 
foot  throttle  if  necessary,  as  is  very  often  the  case  when  running  over 
a  heavy  road. 


622 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          623 

To  Change  to  High  Speed. — This  is  the  speed  of  direct  drive 
and  in  shifting  the  gears  for  this  speed,  the  driver  proceeds  in 
the  same  manner  just  described  for  changing  to  second  speed, 
that  is,  after  releasing  the  clutch,  the  transmission  lever  is  moved 
to  the  high  speed  position,  and  then  the  clutch  is  gradually  re- 
engaged or  thrown  in  again. 

In  the  four  speed  transmission  there  is  an  additional  speed  to  pass 
through,  but  the  same  operations  as  just  described  are  performed. 

In  some  four  speed  transmissions  the  direct  drive  is  the  fourth  speed, 
while  in  others  the  construction  is  such  that  the  direct  drive  is  on  the 
three  speed,  the  fourth  speed  gearing  the  engine  to  run  slower  than  the 
propeller  shaft. 

Throttle  and  Spark  Control. — In  running  the  car,  the  speed 
is  almost  entirely  regulated  by  the  throttle,  the  accelerator,  or  foot 
pedal  being  used  mostly. 

The  hand  throttle  lever  is  used  occasionally  as  a  relief,  to  prevent 
fatigue  of  the  ankle  muscles,  or  where  the  car  is  run  considerable  dis- 
tances without  speed  changes,  as  on  open  country  roads. 

To  properly  manage  the  spark  under  varied  running  conditions, 
the  driver  should  have  an  understanding  of  ignition  and  car- 
buretter principles  together  with  extensive  experience  in  operat- 
ing the  car.  The  spark  control  will  depend  somewhat  on  the 
kind  of  ignition  used. 

When  a  vibrating  spark  coil  is  used,  no  such  advance  of  the 
spark  is  possible  as  would  be  indicated  by  the  position  of  a  timer 
apparently  capable  of  a  movement  of  90  degrees  or  more.  This 
is  due  to  the  lag  in  vibrating  spark  coils.  Hence,  it  should  be 
remembered  that  with  a  vibrating  coil,  the  spark  position  as  in- 
dicated by  the  spark  lever  is  always  in  advance  of  its  true  posi- 
tion— the  difference  increasing  with  the  engine  speed. 

With  a  high  tension  magneto,  no  such  difference  exists  since 
the  mechanically  operated  interrupter  is  positive  in  its  action. 

The  car  should  always  be  run  with  the  spark  at  least  partially 
advanced  and  the  speed  controlled  with  the  throttle.  The  spark 
should  never  be  advanced  to  its  highest  point  suddenly,  nor  should 
it  be  put  at  full  advance  before  picking  up  speed,  the  advance 
being  made  gradually  as  the  speed  of  the  car  increases. 


624          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

The  spark  position  is  dependent  to  some  extent  on  the  quality 
of  the  fuel  mixture.  The  mixture  at  low  speeds  should  be  richer 
than  at  high  speeds  on  account  of  heat  and  compression  losses. 

In  this  connection  it  should  be  remembered  that  a  lean  and  highly 
compressed  charge  burns  faster  than  a  richer  one  and  the  spark  position 
should  be  modified  to  suit  the  immediate  conditions  of  combustion. 

A  late  spark,  especially  with  a  rich  mixture  causes  the  engine 
to  heat  up  and  results  in  an  increased  consumption  of  gasoline. 

When  on  the  road  the  best  results  are  usually  obtained  by  ad- 
vancing the  spark  lever  as  far  as  possible  without  the  engine 
pounding. 

Rules  for  handling  the  spark  lever  cannot  be  laid  down,  as 
conditions  vary  with  the  kinds  of  roads  being  traveled,  difference 
in  motors,  etc.,  but  a  good  driver  will  not  allow  the  engine  to 
pound.  The  general  practice  among  drivers,  when  desiring  to 
keep  the  engine  running  slowly,  is  to  retard  both  spark  and  throt- 
tle levers  as  much  as  possible,  the  adjustments  being  usually  set 
to  allow  the  engine  to  just  keep  running  under  these  conditions. 
This  practice  is  responsible  for  the  need  of  grinding  in  valves  at 
short  intervals.  With  the  spark  lever  retarded,  the  gas  is  ignited 
so  late  in  the  stroke  that  the  exhaust  valve  opens  before  the 
charge  is  burnt,  consequently  the  gas  at  a  very  high  temperature 
is  passing  between  the  valve  and  its  seat. 

The  cool  gas,  coming  in  on  the  suction  stroke,  will  help  the 
water-cooling  system  to  keep  the  valve  cool,  but  even  with  this 
help  it  will  not  withstand  the  heat  very  long  and  is  soon  warped, 
allowing  leakage  during  the  compression  stroke.  The  remedy  is 
to  adjust  the  throttle  so  that  the  engine  may  be  run  as  slowly  as 
desired  with  the  spark  advanced  so  that  ignition  does  not  take 
place  so  near  dead  center. 

To  Stop  the  Car. — When  making  a  gradual  stop,  1,  the  throt- 
tle may  be  closed  allowing  the  compressional  resistance  of  the 
engine  to  act  as  a  brake,  until  the  car  has  reduced  its  headway, 

2,  the  left  pedal  is  now  depressed  throwing  out  the  clutch,  and 

3,  the  foot  brake  applied  with  the  right  pedal. 

To  made  a  quick  stop,  both  the  clutch  and  brake  pedals  may  be 
pressed  simultaneously  and  the  emergency  brake  set.  In  making 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          625 

a  stop,  the  transmission  lever  should  always  be  placed  in  the 
neutral  position ;  the  throttle  should  be  closed  and  spark  advanced 
so  that  the  engine  will  not  race. 

To  Reverse  the  Car. — After  the  car  has  come  to  a  standstill, 
i,  the  clutch  is  held  out  with  the  left  pedal,  2,  brakes  released,  3, 
the  transmission  lever  moved  to  the  reverse  position,  and  4,  the 
clutch  gradually  thrown  in. 

Shifting  the  Speed  Change  Gears. — The  proper  handling  of 
the  transmission  lever,  on  a  sliding  gear  system,  can  only  be 
obtained  by  practice.  One  of  the  best  tests  of  a  driver's  skill  is 
to  notice  the  way  he  handles  the  change  speed  gears. 

A  skillful  man,  accustomed  to  a  car,  will  pass  through  all 
speeds,  either  up  or  down,  noiselessly,  unless  for  the  click  caused 
by  the  lever  bringing  up  against  the  quadrant. 

In  shifting  the  transmission  lever  for  the  speed  changes,  if  the 
transmission  be  of  the  selective  type,  the  two  movements  neces- 
sary to  give  the  lever  may  offer  some  difficulty  to  the  beginner. 

In  moving  the  lever,  the  driver  gives  it  a  slight  lateral  pressure  as  it 
approaches  the  neutral  point.  With  a  little  practice,  the  change  may  be 
made  with  practically  one  motion,  the  lateral  movement  requiring  no  sepa- 
rate action. 

In  the  mind  of  the  average  demonstrator  and  that  of  his  pupil,  for  the 
latter  has  it  ground  into  him,  there  are  but  two  things  to  do  in  gear  chang- 
ing, release  the  clutch  and  push  or  pull  the  lever. 

The  beginner  pushes  or  pulls  the  lever  mechanically,  and  it  is  usually 
not  until  long  after  he  has  graduated  from  his  novitiate  that  he  comes  to 
learn  what  actually  happens  in  the  gear  box  when  he  moves  the  lever. 

If  a  knowledge  of  the  principles  of  operation  of  a  transmis- 
sion were  first  acquired,  there  would  be  less  difficulty  in  learning 
to  handle  the  lever  correctly. 

In  the  operation  of  the  change  speed  gears,  it  will  be  evident 
that  unless  the  teeth  of  the  two  pinions,  that  it  is  desired  to  mesh, 
happen  to  be  in  a  position  where  they  correspond,  they  cannot 
be  slid  together.  Then  if  both  shafts  be  idle  and  the  gears  do 
not  happen  to  be  in  a  position  where  their  teeth  will  go  together, 
they  must  be  moved.  But,  taking  the  speeds  in  their  usual  order, 
which  makes  the  operation  of  starting  the  first  thing  to  be  con- 


626          AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

sidered,  it  is  evident  that  only  the  clutch  shaft  can  be  moved  as 
the  car  is  standing  still.  This  gives  a  condition  where  one  shaft  is 
idle  and  the  other  is  revolving  at  a  high  speed. 

The  fundamental  requirement  in  every  case  is  that  the  two 
gears  to  be  meshed  shall  be  revolving  at  as  nearly  the  same  speed 
as  possible,  therefore  when  going  into  first  speed  the  necessity 
for  waiting  a  moment  or  two  after  declutching  in  order  to  allow 
the  clutch  shaft  to  slow  down  must  be  plain.  If  the  lever  be 
moved,  immediately  the  clutch  is  disengaged,  it  is  practically  the 
same  as  if  an  attempt  were  made  to  mesh  the  gears  without  go- 
ing through  the  very  necessary  preliminary  of  taking  the  clutch 
out  of  engagement. 

Just  how  long  it  is  necessary  to  wait  must  be  a  matter  of 
experience  on  different  types  of  cars. 

The  old  conical  clutch  with  its  comparatively  great  diameter  is  apt  to 
hold  its  momentum  much  longer  than  other  types  such  as  the  multiple 
disc,  in  which  the  discs  are  very  small  and  very  light,  although  improve- 
ment along  these  lines  has  also  made  a  vast  difference  in  the  earlier  type 
which  is  still  adhered  to  by  a  surprising  number  of  prominent  builders. 

In  any  case,  the  wait  will  not  exceed  a  few  seconds,  but  the  difference 
in  the  result  at  the  end  of  that  time  will  be  very  perceptible  as  the  gears 
are  easily  slid  into  mesh  without  any  noise  when  the  pinion  on  the  clutch 
shaft  is  just  about  to  come  to  rest. 

Waiting  too  long  is  not  as  bad  as  delaying  the  operation  for  too  short 
a  time,  as  the  noise  and  damage  will  be  proportioned  to  the  relative  speeds 
of  the  shafts,  whereas  in  the  former  case,  it  is  merely  a  matter  of  try 
again,  and  a  word  of  advice  here  should  not  come  amiss. 

Gears  should  not  be  forced  into  mesh.  If  they  do  not  engage 
without  being  forced  together,  there  is  something  radically 
wrong,  and  jamming  down  hard  on  the  lever  is  only  liable  to 
aggravate  the  trouble  or  spring  the  shifting  arm  or  lever. 

The  noise  or  growl  so  frequently  heard  is  caused  by  the  attempt  to  force 
the  gears  together  while  they  are  traveling  at  different  rates  of  speed. 
This  serves  to  grind  and  chip  the  edges,  occasionally  breaking  the  teeth. 
No  matter  how  easy  an  entrance  has  been  provided  by  the  designer  of 
the  car,  the  pinions  cannot  be  slid  together  unless  they  happen  to  be 
revolving  at  something  approximating  the  same  rate  of  speed,  and  the 
closer  they  are  to  this,  the  better. 

Observation  shows  that  the  average  driver  seldom  takes  the  precaution 
of  waiting  before  engaging  the  first  speed  to  start,  and  noise  and  damage 
inevitably  ensue. 

On  increasing  to  second  speed,  very  similar  conditions  obtain.  The 
clutch  shaft  is  revolving  at  a  comparatively  high  rate  of  speed  and  the 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          627 

countershaft  is  going  at  a  considerably  slower  rate.  Hence,  it  is  im- 
possible to  make  the  latter  go  any  faster  and  therefore  an  immediate 
and  noiseless  change  is  not  possible. 

The  usual  method  is  to  move  the  side  lever  simultaneously  with  the  re- 
lease of  the  clutch,  and  the  result  is  to  bring  the  speed  of  the  clutch  shaft 
down  to  that  of  the  countershaft  by  the  friction  thus  created  between  the 
sides  of  the  pinions,  to  their  resultant  damage.  The  same  result  can  be 
much  better  accomplished  by  a  momentary  halt  between  the  operation  of 
pulling  the  lever  out  of  one  speed  and  placing  it  home  at  the  other,  keep- 
ing the  clutch  fully  disengaged  in  the  interval.  Here  skill  and  experience 
in  the  handling  of  the  make  of  car  that  one  happens  to  be  driving  count, 
for  if  the  wait  be  prolonged,  the  result  will  be  the  same  as  if  none  had 
been  indulged  in  and  the  stop  is  apt  to  compel  the  momentary  re-engage- 
ment of  the  clutch  to  again  set  the  clutch  shaft  in  motion. 

With  the  progressive  gear  the  system  is  usually  arranged  so 
that  reverse  is  in  mesh  with  the  lever  at  the  extreme  rear  and 
high  speed  at  the  forward  end  of  the  quadrant,  the  intermediate 
speeds  proportioned  in  between.  The  lever  usually  has  a  button 
on  top,  controlling  a  latch  that  locks  it  in  place  at  any  desired 
speed  by  fitting  into  a  slot  cut  in  the  quadrant. 

The  easiest  method  of  securing  the  proper  amount  of  travel, 
from  one  speed  to  another,  is  the  following:  Press  the  button 
or  finger  clasp  that  releases  the  latch  from  its  slot,  and  while 
holding  it  released  move  the  lever  far  enough  to  prevent  its  slip- 
ping back  into  the  slot  when  the  button  is  released.  The  latch 
will  now  be  pressing  against  the  quadrant  bar,  and  the  lever 
can  be  moved  until  the  desired  gear  is  properly  meshed,  where 
the  influence  of  the  spring  will  pull  the  latch  into  the  slot  and 
lock  the  lever.  If  the  latch  be  held  released  the  result  may  be 
that  the  lever  will  be  carried  too  far  into  the  following  neutral.  If 
this  occur  the  best  thing  to  do  is  to  stop  and  come  back  to  first 
speed  again. 

The  progressive  gear,  as  worked  out  by  the  Packard  Company,  does 
not  have  a  locking  device  on  the  lever,  the  same  result  being  obtained 
by  a  device  in  the  gear  box.  When  shifting  from  first  to  second,  or  from 
third  back  to  second,  the  lever  should  be  carried  rapidly  forward  or  back- 
ward until  the  gears  are  felt  to  engage.  The  locking  device,  though  not 
automatic,  will  check  the  travel  of  the  lever,  and  if  the  gears  are  properly 
in  mesh  will  provide  sufficient  resistance  to  the  movement  of  the  lever  to 
assure  the  operator  that  the  gears  are  correctly  in  mesh. 

Drivers  handling  the  selective  system  have  two  things  to  re- 
member. The  first  is  to  keep  it  well  oiled  that  the  lever  may 


628 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


slide  freely  sideways.    The  second  is  to  keep  their  hands  off  the 
button  unless  it  is  desired  to  enter  reverse. 

Some  cars  have  appeared  on  the  market  with  speeds  arranged 
as  follows: 

R  2  4 

i  3 

If  on  a  hill  and  conditions  demand  a  change  to  a  lower  gear,  say,  third 
back  to  second,  the  driver  will  have  no  trouble  if  he  handle  the  lever 
without  touching  the  button.  If  he  does,  he  is  almost  sure  to  enter  re- 
verse, with  possibly  serious  consequences. 

The  clutch  should  be  thrown  as  far  forward  as  possible  before  any 
attempt  is  made  to  engage  the  gears.  (Some  cars  have  appeared  with  only 
one  pedal  so  arranged  that  the  clutch  is  first  released  and  further  travel 
of  the  pedal  applies  the  running  brakes.)  The  different  types  of  clutches 
in  use  and  the  care  bestowed  on  them  has  much  to  do  with  the  ease  with 
which  the  gears  may  be  engaged. 


Flo.  472. — When  two  cars  are  goinj  in  opposite  directions,  the  safe  procedure  is  for  each 
driver  to  keep  well  to  the  right  of  the  crown  of  the  road,  thus  avoiding  the  possibility 
of  a  collision. 

The  cone  clutch,  with  its  comparatively  large  diameter,  is  likely  to  spin 
longer  than  the  multiple  disc.  Any  attempt  to  mesh  the  gears  while  the 
clutch  is  spinning  will  result  in  the  gears  growling,  possibly  chipping  the 
teeth. 

Occasionally  the  shaft  will  stop  so  that  the  teeth  of  one  gear  will  strike 
the  teeth  of  the  other  and  prevent  them  meshing.  If  this  occur,  the  clutch 
should  be  engaged  again  for  an  instant,  thus  letting  the  clutch  shaft  spin, 
and  after  giving  them  time  to  slow  down,  another  attempt  may  be  made 
to  mesh  the  gear. 

City  Driving. — In  driving  an  automobile  in  the  city,  there 
are  certain  fixed  rules  of  the  road  that  must  be  observed,  and 
rightly,  too,  if  one  is  to  avoid  trouble,  but  the  -motto  of  every 
driver  should  be :  "Always  be  prepared  for  everyone  else  doing 
the  wrong  thing."  By  observing  this  rule,  the  driver  will  find 
himself  armed  for  whatever  may  occur  on  the  city  streets. 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


629 


The  first  thing  a  new  driver  should  do  is  to  become  familiar  with  the 
rules  of  the  road.  In  some  places  they  are  unwritten  rules,  but  in  most 
of  the  big  cities  the  police  have  framed  up  regulations  for  the  control  of 
traffic,  which,  unfortunately  in  most  cases,  apply  only  to  motor  cars,  the 
bluecoats  being  singularly  near  sighted  when  it  conies  to  noting  infrac- 
tions of  the  rules  by  drivers  of  horse  drawn  vehicles. 

In  driving  a  car  the  first  rule  is  to  keep  to  the  right  in  passing 
a  vehicle  going  in  the  opposite  direction. 

In  England  the  traffic  stays  on  the  left  side  of  the  road,  but  this  is  the 
exception.  It  is  only  by  everyone  observing  this  rule  that  traffic  can  be 
handled  in  any  kind  of  a  manner,  and  accidents  avoided. 

In  passing  a  vehicle  going  in  the  same  direction  the  rule  is  to 
pass  to  the  left. 


^      • 


Fia.  473.— The  driver  should  not  pass  to  the  right  of  a  vehicle  going  in  the  same  direc- 
tion He  has  no  recourse  in  case  of  an  accident  caused  by  the  other  driver  turning 
into  the  curb. 

Numerous  accidents  have  been  caused  by  failure  to  observe  this  rule. 
The  driver  who  disregards  this  rule  is  liable  for  damages  in  case  of  acci- 
dent, as  a  vehicle  has  the  right  to  swing  to  the  right  at  any  time. 

The  non-observance  of  the  above  rule  is  sometimes  due  to  the  presence 
of  electrics  whose  drivers  generally  stay  in  the  middle  of  the  street  and 
run  at  about  eight  or  ten  miles  an  hour,  which  often  compels  others  to 
invade  forbidden  territory  to  get  by  or  else  swing  to  the  left  directly  into 
the  path  of  the  vehicles  coming  from  the  other  direction.  Cases  are  seen 
daily  where  drivers  have  had  to  go  almost  to  the  left  curb  in  order  to  pass. 

In  turning  corners,  the  driver  should  not  cut  diagonally  across 
the  street  by  beginning  to  turn  before  reaching  the  corner. 

It  is  evident  that  such  a  procedure  will  cut  off  traffic  coming  from  the 
other  direction. 


Road  Signals. — As  laid  down  by  the  makers  of  road  rules, 
the  driver  raises  a  hand  or  whip,  when  he  is  about  to  turn  a 


630  AUTOMOBILE  RUNNING,  CARB  AND  REPAIR. 

corner  or  stop;  the  right  arm  extended  means  that  it  is  unsafe 
for  the  man  behind  to  come  up  on  that  particular  side,  because 
the  signaler  is  preparing  to  turn  a  corner  and  needs  room. 

The  arm  extended  to  the  left  means  caution  on  that  side. 

The  right  arm  raised  so  the  arm  is  above  the  level  of  the  head,  with 
the  forearm  vertical  and  the  shoulder  portion  horizontal,  means  that  speed 
is  about  to  be  slackened,  possibly  because  of  the  traffic  or  because  of 
some  maneuver  the  driver  wishes  to  make. 

It  may  be  a  case  of  reverse ;  then  the  horn  should  be  sounded  to  call 
attention  to  the  signal. 

Another  signal  that  is  sometimes  used  when  a  driver  desires 
the  car  behind  to  pass  him  or  he  has  consented  to  give  the  right 


Flo.  474. — In  turning  corners  where  there  are  pedestrian  refuges  drivers  should  use 
signals,  a  wave  of  the  hand  to  the  right  asking  the  other  driver  to  pause,  while  one 
to  the  left  gives  the  right  of  way. 

of  way  is  to  hold  the  right  arm  downward  outside  the  body  of 
the  car,  and  wave  it  forward. 


Operating  the  Brakes. — The  life  of  tires  may  be  prolonged 
by  the  judicious  and  moderate  handling  of  the  brake  lever.  The 
brake  should  never  be  applied  with  such  force  as  to  cause  the 
tires  to  slip. 

If  the  wheels  be  locked,  much  of  the  retarding  effort  is  lost 
and  much  rubber  is  ground  off  the  tires,  or  if  traveling  on  muddy 
roads  or  pavements  all  control  over  the  car  will  be  lost. 

On  long  grades  the  brakes  should  not  be  depended  on  to  hold  the  car. 
The  ignition  should  be  cut  out,  and,  depending  on  the  length  and  steepness 
of  the  grade,  a  suitable  gear  should  be  meshed  and  the  car  allowed  to 
coast  under  compression,  the  brakes  supplying  any  further  retarding  effort 
necessary. 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


631 


In  driving  in  a  hilly  country,  it  is  desirable,  not  to  have  the  emergency 
brake  lever  interconnected  with  the  clutch,  as  this  prevents  the  use  of  a 
very  efficient  brake. 

Some  brakes  are  intended  to  be  lubricated,  others  are  useless  if  oil  gets 
on  the  friction  surfaces.  When  this  happens  the  best  thing  to  do  is  to 
squirt  a  little  gasoline  on  the  drum.  This  will  cut  the  oil  and  restore 
the  efficiency.  If  one  brake  be  adjusted  tighter  than  the  other  it  will 
throw  the  end  of  the  car  on  that  side  around. 

Friction  surfaces  of  metal  to  metal,  or  steel  to  camel's  hair  or  asbestos, 
will  give  little  trouble  with  ordinary  care. 

If  leather  be  used,  its  life  will  be  prolonged  by  releasing  the  brakes  for 
an  instant  while  in  use.  This  will  allow  a  current  of  air  to  pass  between 
the  surfaces  and  carry  away  a  great  deal  of  the  heat  generated.  The  fric- 
tion of  the  brake  leather  on  the  drum  always  generates  heat,  and  the 
leather  may  be  heated  enough  to  be  burnt  or  charred  until  useless  unless 
the  brake  be  used  with  moderation. 


' 


Pio.  475. — In  turning  corners  the  driver  of  a  vehicle  turning  to  the  left  _f rom  the  right 
hand  side  should  pass  the  center  of  the  street  intersection  before  making  a  turn.  In 
case  he  is  seeking  to  make  a  right  hand  turn  he  should  hug  the  curb  as  closely  as 
possible  in  turning  the  corner. 

Trolley  Lines. — As  a  rule,  the  track  is  laid  on  one  side  of  the 
road,  but  there  appears  to  be  no  recognized  plan  as  regards  loca- 
tion, and  the  autoist  must  keep  a  sharp  lookout,  not  only  for 
surprising  changes  in  the  location  of  the  line  but  also  for  the 
cars  themselves. 

In  regard  to  the  track  itself,  strict  watch  should  be  kept  for 
rails  which  are  elevated  above  the  level  of  the  road,  for  switch 
tongues  and  differences  in  level  between  the  bed  of  the  track 
and  the  surface  of  the  road. 

Any  of  the  above  may  interfere  with  the  steering  of  the  automobile  if 
the  wheels  come  in  contact  with  them,  and  if  the  road  be  at  all  greasy, 
side  slips  are  likely  to  occur. 


632 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


The  rails  are  a  source  of  trouble  when  slippery  and  care  should  be 
taken  that  the  tires  do  not  get  into  the  rail  channels,  as  they  will  be  badly 
wrenched  or  even  torn  off  when  a  change  of  direction  is  desired. 

One  of  the  commonest  mistakes  made  is  in  running  the  car  with  all 
four  tires  in  the  channels,  which  undoubtedly  makes  smooth  riding  but 
which  also  renders  it  difficult  for  the  autoist  to  steer  out  of  them  again 
when  he  wishes  to  do  so  by  any  movement  of  the  steering  gear. 

When  the  rails  are  dry,  only  a  short  time  will  elapse  before  the  tire 
will  ride  over  the  rail  head  and  get  clear,  but  with  wet  rails  sometimes 
hundreds  of  feet  are  traversed  before  the  tires  are  clear. 

Crossing  Railroad  Tracks. — All  railroad  tracks  should  be 
treated  as  if  trains  were  likely  to  be  due  at  the  crossing  at  any 
moment  and  the  car  should  be  driven  across  at  the  greatest  angle 
and  at  the  best  speed  possible.  A  sharp  lookout  should  be  kept 
in  both  directions  and  the  car  slowed  down  on  approaching  the 
crossing,  taking  absolutely  no  chances. 


FIG.  476. — In  making  a  stop,  avoid  facing  the  car  in  the  wrong  direction.     The  rules  of 
the  road  call  for  a  machine  or  vehicle  stopping  with  the  right  wheels  to  the  curb. 

In  case  a  collision  is  imminent,  the  steering  wheel  should  be  turned 
sharply  in  the  direction  in  which  the  train  is  moving  so  that  the  car  will 
be  struck  a  glancing  blow  and  the  occupants  will  have  some  chance  of 
escape. 

Negotiating  Turns. — The  procedure  on  approaching  a  turn 
is  exactly  similar  to  that  on  approaching  a  road  crossing.  The 
car  should  keep  to  the  center  of  the  road  and  its  speed  should 
be  reduced  somewhat  until  the  road  is  seen  to  be  clear  when  the 
turn  can  be  made.  In  taking  a  right  hand  turn,  the  autoist 
should  keep  well  away  from  the  corner,  describing  as  large  an 
arc  as  possible  and  gradually  gaining  the  center  of  the  other 
road.  There  are  numbers  of  drivers  who  habitually  shave 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


633 


corners;  who  start  to  make  the  turn  before  reaching  the  proper 
point  and  cut  diagonally  across  the  road,  obstructing  traffic  com- 
ing in  the  opposite  direction,  and  hugging  the  left  hand  corner 
of  the  intersecting  road.  Their  desire  is  evidently  to  travel  from 
one  point  to  another  in  the  shortest  possible  space  of  time,  and 
to  save  distance  cut  the  corners  without  regard  to  the  rights  or 
safety  of  others. 

Because  of  the  presence  of  reckless  classes  of  drivers,  special 
caution  has  to  be  exercised  at  all  times  by  those  in  charge  of 
vehicles  of  every  kind. 

The  difficulty  of  taking  a  car  around  a  corner  which  has  to  be  turned 
to  the  right  is  sometimes  acute,  since  the  driver  must  keep  to  his  own  side, 
and  on  that  the  camber  of  the  road  adds  seriously  to  any  danger  that 


tia.  477. — A  good  rule  to  observe  and  one  that  will  prevent  accidents  is  to  go  to  the 
next  corner  before  turning  in  a  street.  The  turn  should  not  be  attempted  until  the 
farther  corner  has  been  reached,  then  a  wide  swing  should  be  made,  caution  being 
observed,  of  course,  to  avoid  rigs  going  in  both  directions. 

may  exist  owing  to  mud  or  slime.  Even  when  the  surface  is  quite  dry, 
the  camber  is  sometimes  sufficient,  with  the  acuteness  of  the  turn,  to  cause 
the  rear  of  the  car  to  swing,  and  it  is  because  of  this  that  many  heavy 
cars  are  fitted  with  metal  non-skid  covers  all  the  year  round. 

\Vhere  the  presence  of  an  acute  turn  of  this  description  is  known,  or 
is  indicated  by  a  warning  sign,  the  driver  can  be  relied  upon  to  reduce 
his  speed,  so  as  to  be  able  to  take  it  without  unduly  stressing  his  running 
gear.  But  it  is  when  the  situation  suddenly  presents  itself  that  matters 
assume  a  critical  phase. 

If  the  car  be  still  running  in  a  straight  line  when  the  nature  of  the 
corner  becomes  apparent,  the  engine  should  be  switched  off  and  the  brakes 
judiciously  applied  without  taking  out  the  clutch,  but  if  the  corner 
has  been  entered  upon  the  greatest  care  should  be  exercised  in  using  the 
brakes,  as  to  lock  the  driving  wheels  would  probably  make  a  violent  side- 
slip inevitable. 


634  AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

If  the  corner  has  been  entered  upon,  it  will  be  wise  to  withdraw  the 
clutch  and  trust  to  gentle  braking  with  the  side  lever  and  good  steering 
to  get  round.  Every  broken  bit  of  road  surface  should  be  taken  advantage 
of  to  assist  the  driving  wheels  to  hold  to  the  road. 

To  take  a  greasy  corner,  turning  on  the  off  or  right  hand  side  is  easy 
enough  since,  the  driver  being  on  his  own  side,  can  put  the  innerside 
wheels  in  the  gutter — where  they  act  as  non-skids  against  the  slope  of  the 
latter — and  run  round  cautiously. 

It  is  best  to  run  free  for  the  sake  of  the  differential  gear  if  the  corner 
be  sharp,  and  if  the  rear  of  the  car  shows  an  inclination  to  swing,  gently 
letting  in  the  clutch  will  cause  the  inside  wheel  to  "bite,"  and  the  car  will 
answer  the  helm. 

Country  Driving. — On  a  country  road  the  farmer  will  either 
give  the  motorist  the  whole  road  or  won't  move  until  he  has  to. 
He  isn't  a  bit  particular  whether  he  turns  to  the  right  or  left. 


Pia  478. — The  American  Motor  League  "caution  signs."  Background 
and  posts  white,  symbols  black;  1  indicates  approach  to  a  steep 
descent;  2,  approach  to  a  railroad  crossing;  3,  approach  to  a  branch 
road  i  to  ^ight);  4,  approach  to  a  branch  road  (to  left);  5,  approach 
to  cross  roads;  6,  approach  to  a  ditch  or  abrupt  depression  in  the 
road;  7,  approach  to  a  hummock;  8,  approach  to  a  city,  village  or 
other  collection  of  inhabited  dwellings;  9,  is  a  general  caution 
signal  indicating  me  proximity  of  any  danger  or  obstruction  not 
scheduled  above,  or  any  other  condition  requiring  caution;  10  (not 
shown  in  cut)  is  a  pla:r  white  sign  and  can  be  improvised  In  emer- 
gent cases  by  using  a  shefr  of  white  cloth  fastened  upon  a  board 
of  proper  shape.  Each  sign  IP  spaced  at  a  distance  of  not  less  than 
200.  nor  more  than  300  yards  from  *he  point  to  which  it  refers. 

Similarly  when  following  and  trying  to  overtake  another  auto- 
mobile on  the  road,  the  uriver  of  the  leading  machine  may  try 
to  prevent  the  other  car  passing  him,  or  may  take  that  side, 
of  the  road  that  looks  best  to  him  regardless  of  rules  or  laws. 
When  passing  little  breaks  in  the  road  caused  by  water  running 
off  and  carrying  the  road  material  with  it,  holes  in  pavement, 


'AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 


635 


etc.,  the  shock  of  striking  the  edges  is  rather  severe  on  tires  and 
imy  be  lessened  by  releasing  the  clutch  for  the  moment  and 
allowing  the  car  to  coast,  always  taking  "waterbreaks"  and  simi- 
lar rough  spots  straight  on,  so  as  not  to  strain  the  car  unneces- 
sarily. 

On  approaching  a  point  where  the  road  forks  or  branches  off, 
the  antoist  should  hold  well  over  to  the  proper  side  of  the  road 
in  order  to  moid  cars  coming  along  the  branches. 

Should  he  be  traveling  along  one  of  the  branches  toward  the  fork,  how- 
ever, he  should  keep  in  the  center,  as  when  approaching  an  ordinary  turn. 


FIG.  479. — S'ow  moving  vehicles  should  keep  as  near  the  curb  as  possible,  leaving  tb« 
left  side  of  that  side  of  the  road  for  faster  moving  rigs. 

Skidding  and  Side  Slipping. — Although  both  the  terms  skid- 
ding and  side  slipping  are  used  freely,  their  meanings  are  often 
confused. 

Skidding  implies  a  continued  forward  movement  of  the  car 
after  the  wheels  have  been  locked  by  the  brakes. 

Side  slipping  relates  only  to  a  lateral  motion  of  the  car  due 
to  the  wheels  sliding  bodily  sideways. 

Nothing  but  experience  can  teach  the  autoist  how  to  evade  side  slip 
when  the  roads  are  in  a  slippery  state.  He  may  be  forewarned  of  the 
various  kinds  of  side  slips  and  skids  and  the  proper  procedure  under  the 
circumstances,  but  he  must  actually  experience  each  kind  in  order  to  dis- 
tinguish one  from  the  other  and  to  acquire  the  instinct  necessary  to  coun- 
terbalance every  tendency  in  that  direction  immediately  the  first  symptoms 
are  perceptible. 


636  AUTOMOBILE  RUNNING,  CARS  AND  REPAIR. 

There  are  certain  kinds  of  surface  on  which  the  tires  cannot  obtain  a 
firm  grip,  places  in  which  lateral  strains  are  brought  to  bear  on  the 
car,  and  acts  on  the  part  of  the  driver  which  either  reduce  or  increase 
the  adherence  between  the  tires  and  the  road. 

Deft  manipulation  of  the  steering  wheel  by  an  expert  operator  often 
will  neutralize  a  well  developed  skid,  by  maintaining  the  car  in  approxi- 
mately its  original  line  of  onward  movement. 

Thus,  if  the  front  wheels  be  steered  in  the  direction  in  which  the  rear 
wheels  are  skidding,  the  tendency  of  the  vehicle  is  to  stay  parallel  to  its 
original  line  of  movement,  ready  to  resume  it  as  the  skidding  terminates. 

Operating  a  Car  at  Night.- — Objects  at  night  are  deceiving  to 
the  eye.  What  appears  as  a  dark  patch  in  the  road  may  be  either 
a  pool  of  water  or  a  depression,  and  light  colored  objects  by  the 
side  of  the  road  may  even  be  taken  for  the  road  itself.  The 
road,  too,  apparently  disappears  a  short  distance  ahead  and  the 
autoist  sets  the  brakes,  only  to  find  himself  deceived.  Due  to  the 
combination  of  deep  shadows  and  strong  lights  with  the  general 
gloom  of  the  night,  all  sorts  of  objects  created  in  the  imagina- 
tion seem  to  spring  up,  causing  doubt  and  anxiety. 

Powerful  lamps  should  be  used  for  comfortable  night  driving 
as  well  as  for  the  safety  of  the  occupants  of  the  car. 

Running  in  city  streets  or  on  lighted  roads  is  of  course  much  easier 
than  running  on  dark  roads,  but  in  such  cases  the  eyes  are  constantly  ac- 
commodating themselves  to  the  changes  in  light  as  the  car  approaches 
and  passes  a  street  lamp. 

With  the  powerful  arc  lights  in  use  in  many  cities,  the  view  will  be 
obscured  for  a  short  time  as  the  car  passes  out  of  the  circle  thrown  by 
the  light  and  a  feeling  of  blindness  will  result,  soon  passing  off,  however, 
as  the  eyes  adjust  themselves  to  the  change  in  quality  of  the  light.  It  is 
due  to  this  effect  on  the  eyes  that  a  number  of  the  minor  accidents  occur 
at  corners,  not  only  to  autos  but  to  horse  vehicles  and  foot  passengers. 

When  emerging  from  light  into  what  seems  total  darkness,  as  when 
leaving  the  last  light  of  a  city  and  going  along  the  unlighted  road,  an  in- 
voluntary sensation  of  being  lost  is  experienced  and  even  with  powerful 
headlights  the  feeling  of  blindness  occurs  for  a  short  time. 

Goggles  to  be  Avoided  at  Night. — Except  when  absolutely 
necessary,  goggles  should  not  be  worn  nor  should  the  wind  shield 
be  raised  when  driving  at  night,  as  the  reflections  from  street- 
lamps  or  other  sources  of  light  on  the  glass  surfaces  of  the  gog- 
gles and  shield  appear  as  direct  lights  and  obscure  objects  on  the 
road,  with  unhappy  results. 


AUTOMOBILE  RUXXIXG,  CARE  AND  REPAIR. 


637 


Lamp  Equipment.— For  properly  illuminating  the  road  and 
objects  surrounding:  it  the  lamp  equipment  should  consist  of: 

1.  One  or  two  headlights; 

2.  Pair  of  side  lamps; 

3.  Tail  lamp; 

4.  Swivelling  searchlight. 

The  headlights  should  be  carried  low  down  and  well  fonvard, 
not  only  to  better  illuminate  the  road  but  to  cease  to  dazzle  other 
road  users. 


Flo.  480. — The  Pullman  four  cylinder  car  (model  K);  engine  4Jx4j  water  cooled,  rated  at 
30  horse  power;  selective  transmission;  shaft  drive;  two  double  high  tension  ignition 
system — Bosch  magneto  and  dry  cells. 

Overhauling  the  Car. — A  thorough  overhauling  of  the  entire 
car  is  occasionally  required,  that  the  needed  repairs  may  be  made. 
It  is  only  by  this  thorough  overhauling  that  the  owner  can  get  a 
good  idea  of  the  car's  condition,  ascertain  what  parts  show  wear, 
and  correct  wrong  adjustments  which  may  have  been  previously 
made. 

The  principal  reason  for  taking  an  engine  apart  is  to  find  the 
exact  condition  of  the  pistons  and  bearings,  as  well  as  to  clean 
out.  thoroughly  any  carbonized  oil  that  may  be  found  adhering 
to  the  cylinder  walls. 

Each  part  as  it  is  removed  should  be  cleaned.  As  soon  as 
one  part  is  unjointed  or  uncoupled,  insert  its  pins  or  screws  in 
their  proper  place  before  laying  aside.  This  will  prevent  any 
small  parts  being  misplaced. 


638  AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

Confusion  is  to  be  avoided  by  providing  a  sufficient  number 
of  boxes  to  accommodate  the  several  units  of  the  car,  and  keep 
everything-  pertaining  to  a  certain  part  in  its  respective  box. 

In  overhauling  the  car,  the  carburetter,  pump,  wiring,  spark  plugs  and 
any  other  movable  parts  fastened  to  the  engine  should  be  removed. 

When  removing  the  magneto,  the  gear  wheels  of  the  engine  and  the 
driving  pinion  of  the  armature  shaft  should  be  marked  with  a  punch  at 
the  point  where  they  mesh,  if  not  marked  already.  By  taking  this  precau- 
tion the  magneto  may  be  assembled  on  the  car  in  its  proper  place  without 
disturbing  ;he  original  ignition  timing  of  the  car.  Each  valve  should  be 
marked  as  it  is  taken  out,  that  each  may  be  replaced  in  its  proper  seat.  It 
will  be  convenient  to  number  them  i,  2,  3,  etc.,  by  punch  mark. 

The  cylinder  castings  may  now  be  lifted  off  the  pistons  and  removed 
to  the  work  bench.  Some  workmen  prefer  to  lift  cylinders  and  pistons 
off  together;  this  is  a  good  plan  if  a  helper  be  at  hand,  but  more  difficult 
for  one  man  than  lifting  the  cylinder  alone.  In  assembling,  however,  with- 
out assistance,  and  especially  when  the  cylinders  are  cast  in  pairs  or  en 
bloc,  the  weight  of  the  cylinder  casting  is  considerable,  and  it  is  much  less 
laborious  first  to  assemble  the  cylinders  with  the  pistons  in  their  jespec- 
tive  places,  and  so  avoid  holding  up  the  heavy  casting  while  fitting  the 
pistons. 

The  connecting  rods  should  be  uncoupled  from  the  crank  shaft,  the 
rods  and  pistons  being  removed  together. 

Before  taking  down  any  other  part  of  the  car,  it  is  a  good  plan  to  first 
clean  out  the  cylinders  with  kerosene  to  remove  any  oil  and  so  soften  de- 
posits of  carbon  adhering  to  the  walls.  If  the  deposit  be  light,  this 
soaking  may  be  all  that  is  necessary,  but  where  a  considerable  amount  of 
carbon  has  gathered  in  the  combustion  chamber,  the  walls  must  be  scraped 
either  with  a  suitable  carbon  scraper  sold  for  this  purpose,  or  with  a  file 
bent  and  sharpened  to  a  cutting  edge. 

All  the  piston  rings  should  be  clean  and  bright ;  if  any  black  streaks 
be  found,  it  is  a  certain  indication  of  leakage.  A'l  worn  piston  rings 
should  be  replaced.  Examine  the  piston  pin  with  a  view  to  possible  loose- 
ness and  wear.  It  is  important  that  this  pin  should  be  a  tight  fit,  other- 
wise it  may  work  out  and  injure  the  cylinder  walls.  A  loose  piston  pin 
may  be  due  to  the  set  screw  becoming  loose,  or  it  may  be  caused  by  wear. 
In  the  latter  event,  the  pin  should  be  replaced  with  a  new  one  of  the 
proper  diameter  and  length. 

The  valves  should  be  ground.  A  good  grinding  mixture  is  one  com- 
posed of  emery  of  the  grade  known  as  120  mixed  with  kerosene  and  a  few 
drops  of  heavy  lubricating  oil  to  give  the  mixture  body. 

The  camshafts  in  most  cars  are  removed  by  taking  off  the  cover  of  the 
case  which  encloses  the  timing  gears  and  pulling  the  camshafts  through 
this  opening. 

All  modern  cars  have  the  crankshaft  gear  marked,  and  another  mark  be- 
tween the  two  teeth  of  the  timing  gear  on  the  camshaft.  When  assem- 
bling, the  single  marked  tooth  should  be  inserted  between  the  two  teeth 
as  designated.  Breakage  or  undue  wear  of  the  cams  is  a  matter  which 
only  the  factory  experts  can  handle. 

Cleaning  the  radiator  of  grease  or  any  scale  that  may  have  accumulated 
is  best  done  after  the  car  is  reassembled  and  in  running  order.  In  clean- 
ing the  radiator  a  cleaning  mixture  is  made  by  dissolving  one-half  pound 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.  639 

of  lye  in  a  bucket  of  water,  stirring  until  dissolved.  This  should  be 
strained  and  the  radiator  filled  with  the  mixture.  The  engine  should  now 
be  run  for  five  minutes  and  then  allowed  to  stand  for  one-quarter  of  an 
hour.  The  mixture  may  now  be  drained  off  and  the  radiator  filled  with 
civ  an  water.  The  engine  is  again  run  for  a  few  minutes  after  which  the 
radiator  is  drained  and  refilled  with  a  fresh  supply  of  water.  The  forego- 
ing treatment  will  remove  any  grease  deposits  in  the  radiator. 

The  transmission  cover  should  now  be  removed  and  the  gears  examined. 
As  most  transmission  systems  are  fitted  with  annular  ball  bearings,  only 
a  good  cleaning  to  remove  old  grease  will  be  required.  In  case  any  gears 
are  badly  worn  and  their  edges  chipped,  they  should  be  replaced  with  new 
ones. 

The  clutch  may  next  be  taken  down.  The  exact  mode  of  procedure 
differs  in  different  car  clutches.  In  most  cars  using  clutches  of  the  multi- 
ple disc  type  it  may  be  removed  as  a  unit;  in  other  forms,  the  shaft  con- 
necting the  shifting  sleeve  may  be  uncoupled,  which  gives  sufficient  room 
between  clutch  and  gear  box  to  take  the  clutch  apart.  If  the  latter  be 
of  the  cone  type,  it  may  be  found  that  the  leather  face  is  badly  worn 
and  that  a  new  leather  is  necessary.  This  is  not  a  very  difficult  job,  but 
requires  painstaking  work. 

The  leather  of  a  cone  clutch  is  removed  by  cutting  off  the  rivets  on  the 
underside  and  driving  the  rivets  through  to  the  outside.  The  old  leather 
should  be  kept  for  use  as  a  pattern  by  which  to  cut  the  new  piece.  It  will 
be  much  better,  however,  to  purchase  from  the  factory  a  new  leather  of 
the  proper  width  and  thickness.  As  a  new  leather  will  have  considerable 
"give,"  it  must  be  stretched  tightly  over  the  cone.  One  end  of  the  leather 
should  be  cut  square  and  fastened  to  the  cone  with  two  rivets ;  the  other 
end  brought  around  to  meet  the  fastened  end,  and,  after  tightly  stretch- 
ing it  over  the  small  end  of  the  cone  with  a  single  rivet,  the  leather  is 
then  forced  up  onto  the  cone,  holes  drilled  out  and  countersunk  and  the 
leather  riveted. 

The  only  knack  in  the  operation  is  to  keep  the  leather  tight  that  it 
may  be  a  snug  fit  on  the  cone.  A  loose  leather  will,  naturally,  be  a  dead 
failure.  After  the  leather  has  been  forced  into  its  place  the  uncut  end 
should  be  trimmed  to  make  a  good  joint.  Any  unevenness  may  be  trued 
up  with  a  file.  The  new  leather  will  readily  absorb  several  applications 
of  castor  oil  before  it  becomes  smooth  and  pliable. 

Care  should  be  taken  that  the  rivet  heads  are  countersunk  below  the 
surface  of  the  leather.  In  case  they  work  flush,  owing  to  the  wearing 
down  of  the  leather  face,  they  should  be  again  riveted.  The  '"biting"  or 
jerky  action  of  a  cone  clutch  may  often  be  traced  to  the  rivets  working 
out,  and  this  will  frequently  prevent  the  clutch  being  readily  disengaged. 
Reriveting  will  prove  an  effective  remedy  in  this  case,  and  considerable 
additional  service  may  be  had  from  the  leather  before  it  wears  down  to 
the  rivet  heads. 

The  differential  gear  should  be  tested  with  a  view  to  locating  any  wear 
or  side  play.  This  may  be  done  by  jacking  up  the  rear  axle  and  shaking 
one  wheel  forward  and  backward  while  the  other  is  held  stationary,  and 
noting  how  far  the  wheel  must  be  turned  before  the  movement  is  taken 
up  by  the  flywheel  of  the  engine.  Any  noticeable  play  will  generally  be 
found  either  in  the  center  pinions  or  studs  of  the  differential  gear,  in  the 
large  and  small  bevel  gears,  in  the  clutch  sleeve,  or  in  the  universal  joints. 
The  differential  gear  and  live  axle  of  modern  cars  seldom  give  trouble  if 


640  AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

kept  properly  lubricated,  and  the  car's  mileage  should  run  up  into  many 
thousands  before  any  considerable  amount  of  play  is  evident. 

The  joint  pins  of  the  propeller  shaft  may  become  loose  through  wear, 
in  which  case  a  knocking  noise  in  the  transmission  gear  will  indicate  the 
cause  and  location  of  the  trouble.  These  pins  may  be  readily  replaced 
with  new  ones  at  small  cost.  If  the  play  be  found  in  the  bevel  gears,  the 
small  gear  should  be  adjusted  to  mesh  deeper  with  its  larger  mate.  This 
may  be  done  by  means  of  the  adjustable  locking  ring  or  by  inserting  a 
washer  of  the  proper  thickness.  It  may  be  found,  however,  that  no  ad- 
justment is  necessary,  and  a  thorough  cleaning  with  gasoline  to  remove 
all  oil  and  grease  will  be  all  that  is  required.  The  case  should  then  be 
refilled  with  the  quantity  of  oil  and  grease  recommended  by  the  manufac- 
turers. 

Oil  pipes  or  "leads"  which  conduct  the  oil  to  the  bearings  should  be 
removed  and  all  oil  washed  out  by  forcing  gasoline  through  them. 
Care  should  be  taken  that  the  passages  of  all  oil  leads  are  clear  and  un- 
obstructed. 

The  oil  pump  should  be  taken  apart  and  given  a  thorough  cleaning 
with  gasoline. 

The  sight  feed  lubricator  on  the  dash  should  also  be  cleaned  out  and 
the  glasses  wiped  and  washed  out  with  gasoline. 

The  steering  gear  should  be  taken  down,  given  a  thorough  cleaning 
and  examined  for  possible  wear.  In  case  the  steering  action  be  stiff  and 
the  wheel  turn  hard,  the  ball  joint  may  be  out  of  adjustment  due  to  wear; 
the  steering  link  may  be  bent,  or  the  cause  may  be  insufficient  lubrication. 

If  there  be  any  considerable  amount  of  backlash,  the  cause  may  be 
looked  for  in  the  joints  of  the  levers,  in  the  swivel  pin,  in  loose  bearings, 
or  in  wear  of  the  worm  and  sector.  Another  common  cause  of  backlash 
is  often  found  in  the  wheels,  which  work  out  of  alignment.  It  is  essen- 
tial that  all  moving  parts  of  the  steering  gear  be  well  lubricated. 

The  distance  rod  is  easily  bent,  which  throws  the  front  wheels  out  of 
line.  This  is  a  common  cause  of  "side  slip"  and  rapidly  wears  out  the 
tread  of  the  tire.  The  bent  rod  should  be  uncoupled  and  carefully  straight- 
ened. On  many  cars,  however,  the  rod  is  designed  to  be  bent,  in  order 
to  clear  other  parts. 

Each  wheel  should  be  removed  and  examined  at  the  hub  to  see  if  the 
spokes  have  become  loosened  through  shrinkage.  Although  this  is  not 
a  common  fault,  it  is,  nevertheless,  worth  looking  for.  If  slightly  loose, 
tighten  up  the  bolts  which  secure  the  two  side  flanges  together,  clean  out 
bearings  with  gasoline  and  renew  any  ball  or  roller  which  is  found  dam- 
aged. If  rust  has  accumulated,  scrape  or  sandpaper  it  off  (a  painter's 
wire  brush  is  a  handy  tool),  and  when  perfectly  clean,  coat  the  rim  with 
beeswax.  This  may  be  applied  with  a  clean  paint  brush  if  the  wax  be 
heated  to  a  liquid  state.  This  will  effectually  prevent  further  rusting  of 
the  metal,  and  will  do  much  to  preserve  the  life  of  the  tires. 

The  brakes  should  be  examined  to  ascertain  if  the  lining  be  in  good  con- 
dition. If  worn,  the  old  lining  should  be  replaced  with  new.  If  the  brakes 
be  of  the  internal  expanding  type,  the  shoes  may  have  become  worn,  in 
which  case  they  should  be  renewed.  Toggle  joints  and  adjusting  nuts 
should  be  inspected  and  any  looseness  taken  up.  Brakes  should  be  ad- 


AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          641 

justed  on  the  road,  as  any  improper  adjustment  of  the  equalizer  bar  will 
have  a  strong  tendency  to  make  the  car  skid.  Both  brakes  should  be 
adjusted  alike,  that  the  braking  force  applied  by  the  equalizer  may  be 
transmitted  to  the  wheels  equally. 

The  tires  should  be  cleaned  of  the  old  chalk  on  the  inside  of  the  shoe. 
If  they  be  badly  worn  on  the  treads,  but  otherwise  in  good  shape,  send 
them  to  the  factory  to  be  retreaded.  A  tire  should  never  be  kept  on  the 
car  after  the  rubber  tread  wears  down  so  as  to  expose  the  fabric.  Any 
small  cuts  and  holes  should  be  washed  out  and  filled  with  rubber  solution. 

Inner  tubes  should  be  tested  for  leaky  valves  and  patches  attended 
to  at  once.  The  old  casings  and  tubes  may  be  made  to  give  considerable 
additional  mileage  by  using  them  on  the  front  wheels,  where  the 
strain  is  not  so  severe. 

In  overhauling  the  ignition  apparatus,  worn  wires  should  be  replaced 
with  new  ones  to  guard  against  breaks  or  partial  breaks.  A  timer  should 
be  cleaned  with  gasoline  and  lubricated  with  light  oil. 

The  magneto  need  not  be  taken  apart,  as'  it  will  probably  only  need 
a  little  surface  cleaning,  a  few  drops  of  oil,  and  the  amateur  had  better 
not  meddle  with  its  internal  mechanism. 

The  storage  battery  should  be  examined,  and  if  the  brown  deposit  col- 
lect in  any  quantity  at  the  bottom,  the  electrolyte  should  be  poured  out 
into  a  glass  bottle  and  the  battery  washed  out  with  clear  water  (rain 
water  preferred).  Clean  the  top  of  the  battery  and  make  it  a  point  to  keep 
it  clean  and  free  from  acid.  Clean  the  terminals  of  any  corrosion  and 
see  that  the  air  vents  are  not  clogged  up.  If  the  accumulator  has  been 
neglected,  either  in  the  electrolyte  having  been  allowed  to  get  below  the 
proper  level  or  in  not  giving  it  the  regular  monthly  ''charge,"  it  may  get 
a  bad  case  of  sulphating. 

To  get  the  battery  into  its  normal  condition  the  electrolyte  should  be 
emptied  and  the  case  thoroughly  washed  with  soft  water.  The  case  is  then 
refilled  with  about  seven-eighths  of  the  electrolyte  and  the  remainder 
with  soft  water.  In  case  the  plates  are  broken  down  or  "buckled,"  or 
if  the  paste  has  dropped  out  of  the  pockets  in  the  grids,  the  accumulator 
should  be  sent  to  the  manufacturers  for  repair. 

The  contact  points  of  the  coil  will  probably  require  adjusting.  This 
is  easily  accomplished  by  trimming  up  the  points  with  emery  paper. 
Do  not  rub  away  the  metal  unnecessarily,  only  removing  enough  to  true 
the  points  so  that  they  make  a  good  contact.  In  adjusting  the  vibrator, 
remember  that  a  light  tension  is  much  better  than  a  stiff  tension.  A 
light  flexible  vibration  with  a  moderately  high  pitched  buzzing  note  will 
not  only  give  a  better  spark,  but  will  keep  the  points  in  better  shape.  A 
heavy  tension  will  make  the  coil  less  responsive  and  will  pit  the  contact 
points  and  exhaust  the  battery  more  quickly.  As  a  coil  will  render  the 
most  efficient  service  only  when  the  vibrators  are  adjusted  as  nearly  alike 
as  possible,  a  special  ammeter  is  often  used  to  determine  the  current  con- 
sumption of  each  unit.  The  ammeter  should  show  a  reading  of  6-10  am- 
peres. 

Assembling  after  Overhauling. — This  should  be  done  as  soon 
as  possible  after  taking  down  and  cleaning,  to  guard  against  the 
loss  of  any  of  the  parts. 


642  AUTOMOBILE  RUNNING,  CARE  AND  REPAIR. 

In  assembling  the  car,  the  engine  had  best  be  put  together  first. 
When  putting  the  pistons  in  their  respective  cylinders  see  that 
the  splits  or  joints  in  the  piston  rings  are  not  in  line,  but  are 
spaced  evenly  around  the  piston.  See  that  all  parts  are 
thoroughly  clean  and  that  no  grit  or  stray  strands  of  waste 
remain  on  any  projection. 

All  nuts  and  bolts  should  be  screwed  tight  and  the  jaws  of  the 
wrench  should  be  properly  adjusted  to  them,  that  the  corners 
of  the  nuts  and  cap  screws  may  not  be  rounded  off.  Insert  the 
cotter  pin  after  each  nut  has  been  screwed  home.  In  joints  where 
packing  is  required  the  old  packing  may  be  used  if  it  be  in  good 
shape.  Joint  faces  should,  of  course,  be  perfectly  clean.  A  stout 
grade  of  manila  wrapping  paper  soaked  in  linseed  oil  will  make 
an  excellent  packing  for  crankcase  and  other  joints  having  a 
good  contact  surface. 

While  the  engine  is  being  reassembled  it  will  be  found  advantageous 
to  check  up  the  valve  timing.  To  do  this,  turn  the  fly-wheel  until  the  in- 
let valve  plunger  of  No.  i  cylinder  just  touches  the  lower  end  of  its  valve 
stem.  At  this  point  the  line  on  the  fly-wheel  indicating  "Inlet  No.  i  Open" 
should  coincide  with  the  pointer  on  the  engine  base.  If  the  contact  be- 
tween the  valve  stem  and  the  plunger  be  made  before  the  mark  on  the 
fly-wheel  lines  up  with  the  pointer,  the  valve  opens  too  early. 

In  most  cars  the  adjustments  may  be  made  by  the  screw  cap  and  lock 
nut  on  the  plunger. 

As  the  valve  stems  are  lowered  by  repeated  grindings  of  the  valves, 
the  plungers  require  adjustment  occasionally  to  compensate  for  this  move- 
ment. Insert  a  piece  of  paper  between  plunger  and  valve  stem,  and  by- 
lightly  pulling  on  the  paper  the  time  of  contact  and  the  moment  of  re- 
lease may  be  determined  to  a  nicety.  When  the  paper  is  held  tightly,  a 
good  contact  is  assured,  and  the  moment  the  paper  becomes  loose  and  can 
be  moved  about,  the  contact  is  broken.  In  many  cars  the  reference  or  in- 
dex mark  on  the  engine  bed  is  omitted ;  in  this  case  the  markings  on  the 
fly-wheel  must  be  brought  directly  to  the  top.  The  other  inlets  and  the 
exhaust  valves  should  then  be  similarly  checked  up  and  adjusted. 

Most  cars  base  the  valve  setting  on  a  i-32-inch  clearance  space  between 
valve  stem  and  plunger  rod  when  the  valve  is  closed.  This  may  be 
taken  as  the  minimum  amount,  and  should  not  be  increased.  A  larger 
amount  of  clearance  will  cause  the  exhaust  valve  to  open  too  late,  and, 
the  exploded  gases  not  being  entirely  expelled,  the  power  of  the  motor 
will  be  impaired.  This  clearance  is  necessary  to  allow  for  the  expansion 
of  the  valve  stem  when  it  becomes  heated. 

Too  much  stress  cannot  be  laid  on  the  necessity  of  going  about  the 
work  in  an  orderly  and  methodical  manner.  A  mechanic  who  leaves  parts 
lying  about  carelessly  will  rarely  be  found  a  good  one,  and  certainly  he 


'AUTOMOBILE  RUNNING,  CARE  AND  REPAIR.          643 

is  not  n  proper  model  for  the  amateur  to  copy.  With  the  proper  circum- 
spection, then,  and  with  a  little  "horse  sense"  in  applying  the  directions 
to  his  particular  make  of  car,  the  amateur  owner  should  have  no  diffi- 
culty in  making  a  good  job  of  overhauling,  thus  bettering  the  condition 
of  his  machine  and  at  the  same  time  acquiring  a  valuable  stock  of  knowl- 
edge for  the  future. 

Accident  Preventer. — Attached  to  the  wall  at  the  corner  of  a 
narrow  street  leading  into  the  market  place  of  Woodbridge,  Suf- 
folk County,  England,  is  a  mirror  which  makes  it  possible  for  auto- 
mobilists  coming  from  either  direction  to  look  around  the  corner 
and  thus  avoid  collisions.  The  idea  is  being  copied  quite  exten- 
sively. 


FIG.  481. — Kit  of  tools  as  usually  carried  on  an  automobile.  With  this  outfit,  the  driver 
can  make  adjustments  and  repairs  such  as  arise  from  the  ordinary  mishaps  likely  tc 
oe  en  countered  on  the  road. 


WORDS  OF  CAUTION. 


A  plea  for  sanity  and  moderation — Moderation, 

says  Charles  Clifton,  President  of  the  Ass'n  of  Licensed  Auto- 
mobile Manufacturers,  is  the  great  decreaser  of  expense  and 
augmentor  of  enjoyment.  He  writes  as  follows : 

Quotation. — "Automobile  owners,  as  a  rule,  in  discussing  their 
costs  generally  name  the  great  item  of  expense  as  being  tires, 
and  in  that  connection  they  are  quite  inclined  to  arraign  the 
makers  of  pneumatic  tires  as  being  responsible  for  this  condi- 
tion. These  statements  are  an  individual  expression  of  opinion 
based  on  more  or  less  experience,  and  doubtless  justified  in 
part  by  the  records  of  bills  paid  by  those  who  buy  tires." 

"These  remarks,  in  the  same  sense,  are  an  individual  ex* 
pression  of  opinion  based  upon  the  same  facts,  and  are  con* 
tributed  in  the  hope  that  they  may  suggest  a  way  of  reducing 
the  sum  total  of  tire  bills,  as  well  as  leading  in  the  direction 
of  safer  and  saner  methods  in  driving,  and  in  the  last  analysis, 
greater  pleasure  from  motor  cars." 

"There  are  three  prime  factoi  b  responsible  for  short  tire 
life.  First,  excessive  speed,  especially  during  the  warm 
months.  Second,  changes  of  direction  at  a  high  rate  of 
speed;  and  third,  excessive  and  unnecessary  use  of  mechanical 
brakes.  My  experience  has  gone  to  prove  that — punctures  ex- 
cepted — the  life  of  tires  is  enormously  prolonged  by  avoiding 
the  above  three  cardinal  enemies  of  the  pneumatic  tire's  lon- 
gevity. So  much  for  the  direct  money  cost,  but  if  these  three 
cardinal  principles  are  insisted  upon  by  owners,  the  liability 
of  accident  will  be  reduced  to  a  minimum,  and  all  the  high 
costs  incident  to  property  and  personal  da-mage." 

644 


"Accidents  will  also  be  reduced,  as  well  as  wear  and  tear 
mentally  on  an  owner  in  connection  therewith.  In  other 
words,  sanity  in  the  use  of  the  motor  car  is  an  incalculable 
money  value  •which  no  owner  should  ignore ;  and  the  reverse 
of  the  proposition  is  an  unnecessary  extravagance,  which,  if 
indulged  in,  should  not  carry  -with  it  an  invective  against  the 
tire  manufacturer  or  the  manufacturer  of  the  motor  car." 

"In  other  •words,  the  responsibility  for  high  costs  in  running 
expenses  is  absolutely  in  the  hands  of  the  owner,  or,  perhaps, 
more  directly  in  the  hands  of  the  driver.  Excessive  speed, 
under  all  conditions,  is  done  at  high  cost,  -which  abnormal  cost 
can  only  be  reduced  by  the  adoption  of  sane  methods." 

"To  go  a  step  further  in  this  line  of  reasoning,  I  -wish  to 
plead  for  saneness  in  the  use  of  highways.  Not  only  in  the 
matter  of  excessive  speed,  but  also  in  the  relation  -which  should 
subsist  bet-ween  those  who  ride  in  cars  and  those  who  use  it  in 
other  and  older  ways.  The  antagonism  of  the  farmer  against 
the  automobile  is  mainly  the  result  of  a  series  of  circumstances 
•which  to  "the  other  fellow"  seems  like  a  succession  of  out- 
rages. It  is  -well  for  the  driver  of  a  motor  car  to  realize  that 
the  other  fellow  used  the  high-way,  more  or  less  unmolested, 
ever  since  there  were  highways.  That,  -while  he  may  feel  he 
has  pre-emption,  that  pre-emption  goes  no  further  than  the 
joint  use.  For  the  driver  of  a  motor  car  to  assume  to  use 
more  than  his  share  of  the  road  to  make  of  his  vehicle  a 
menace,  or  at  the  very  least  a  nuisance  to  other  users,  is  a 
very  natural  cause  for  antagonism." 

"The  users  and  drivers  of  motor  cars  can,  by  sane  driving, 
do  the  larger  part  in  accomplishing  a  reversal  of  this  senti- 
ment, and  in  any  event  only  fair  play  -will  eliminate  the  present 
friction  -which  none  may  truthfully  deny  exists.*' 


645 


INDEX 

TO    ROMANS'    SELF-PROPELLED    VEHICLES 


Absolute  pressure,  141. 

temperature,  140. 
Absorbing  vibrations,  85. 
Accident  preventer,  643. 
Accidents  to  pneumatic  tires,  119. 
Acid,  should  be  added  to  water,  261. 
\ckerman  axles,  42. 
Acme  igniter,  313,  314. 
Action  of  springs,  74. 
Adams-Farwell  engine,  ills.,  422. 
Adjusting  the  carburetter,  236. 
Adjustment  spark,  after  starting,  431. 

throttle,  after  starting,  431. 
Adjustments,  spark  and  throttle.  426. 
Advantages,  of  double  tires,  115. 

of  scavenging,  174 
After  firing,  250,  445. 
Air  cooling  devices,  101-196. 

for  cylinders,  183,  191. 

requirements  for,  196. 
Air  gap,  auxiliary,  296. 

def.,  256. 

safety,  296. 
Air  inlet  pipe,  247. 

ills.,  247. 

Air,  poor  conductor,  256. 
Air  pressure,  Lane  system,  534. 

Stanley  system.  526. 
Air  supply,  extra,  245. 
Air  valve  spring,  240. 
Alcohol,  comparison  with  gasoline,  254. 

data,  253. 

denatured,  252. 

power  efficiency,  254. 

use  as  fuel,  252-254. 
Alignment  of  springs,  82. 
Alternating  current,  def.,  256. 
American  duplex  gauge,  519. 

igniter,  314. 

Motor  League  caution  signs,  634. 

roller  bearing,  ills.,  406. 

Traveller  gasoline  car,  621. 
Ammeter,  diagram,  562. 
Amperes,  def.,  255. 
Angle,  steering,  diagram,  49. 

how  affected,  51. 
Angular  advance,  effect  of  varying,  469. 


Animal  oils,  why  avoided,  412. 
Apperson,  Elmer,  134. 

on  gasoline  vehicles,  134. 
Apple  dynamo,  diagram,  265. 
Arc,  def.,  256. 

of  steering,  45. 

I u  rning,  of  railroad  wheels,  46. 
Arms,  steering,  ills.,  50. 
Artillery  wheel,  ills.,  of  construction.  93. 

des.,  92. 

Assembling  after  overhauling,  641. 
Asynchronous  drive,  272. 
Atkinson  gas  engine,  180-181. 
Attachment  of  springs,  81. 

of  tires,  ills.,  112,  113. 
Atwater-Kent  spark  generator,  311-313. 
Automobile,  early  history  of,  1-12. 

engines,  operation  of,  415-4501 

essential  elements  of,  14,  15. 

mechanical  history  of,  13. 

types,  132-135. 
Automatic  inlet  valve,  151,  152. 

timing,  352. 
Auxiliary  air  gap,  296. 

spark  gap,  432. 
Axle,  De  Dion-Bouton,    4L 

Haynes-Apperson,  45. 

rear,  Pierce-Racine,  41. 
Axles,  Ackerman,  42. 

pivoted,  42. 

steering,  arrangement  of,  43-45. 

stud,  necessity  for,  1. 

B 

Babcock  electric  roadster,  ills.,  558. 
Back  firing,  429. 

and  back  kick,  429. 

causes  of,  430. 
Back  kick,  427,  429,  430. 
Back  pressure  in  muffler,  178. 
Baker,  Walter  C.,  135. 

on  electric  vehicles,  13&. 
Balance  gear,  16. 
Balance  gears,  necessity  for,  1. 
Balancing  engines,  necessity  for,  323-339. 
Balancing  single  cylinder  engine  324,  326. 
Ball  and  roller  bearings,  401-406. 
Ball  bearings,  403,  404. 

ills..  403. 


647 


648 


INDEX. 


Band  brake,  ills  ,  399. 

Band  brakes,  principles  of,  395. 

Battery  charging  apparatus,  587. 

diagram  for  alternating  current,  589. 

diagram  for  direct  current,  588. 

diagram  of  apparatus,  588. 

method  of  operating,  588. 
Battery  charging  at  night,  589. 
Battery,  defective,  439. 

def.,  257. 

motor  and  controller,  diagram,  598. 

weak,  260,  261,  440. 
Bearings,  ball  and  roller,  401-406. 
Beaumont's  formulae  for  brakes,  395-398. 
Beaumont,  W.  Worby,  quotation  on  tires,  103. 
Before  starting  an  engine,  416. 

a  car,  610. 

Belt  drive,  motor  cycle,  462,  463. 
Benz,  Carl,  mention  of,  3. 

his  gasoline  tricycle,  3. 
Bevel  differential  gear,  ills.,  21. 

drive,  where  advantageous,  30. 

gear,  17,  19,  35. 

gears,  ills.,  18. 

B.  G.  v.  R.  carburetter  ills.,  241. 
Block  chains,  27. 
Blow  off  cock,  522. 
Boiler  attachments,  513-522. 

feeders,  .513. 

tubes,  489. 
Boilers,  controlling  circulation,  490. 

Gurney's,  ills.,  of,  6. 
Boilers,  heavy  truck,  488. 

table  of  sizes,  489. 
Boilers,  heating  surface,  486. 

Maceroni  and  Squire's,  6,  7. 

scale  deposit  in,  490. 

small  shell,  485. 

table  of  sizes,  488. 

Summers'  and  Ogle's,  6,  7. 

tubular  in  general,  487. 

water  tube,  491. 

water  tube  advantages  of,  491. 
Bosch  ignition  system,  806,  307. 

spark  plug,  277-279. 
Boyie's  law,  138,  478. 
Brake,  formula;,  398,  399. 

horse  power,  203. 

horse  power,  formula  for,  204. 
Brakes,  action  of,  398. 

band,  principles  of,  395. 

Beaumont's  formulae  for,  395-398. 

care  of,  400,  640. 

construction  and  operation,  394-400. 

genera!  requirements,  394. 


B  rakes — Con  tinutA. 

levers,  612. 

locomobile,  ills.,  400. 

motor  cycle,  466. 

operating,  630. 

on  long  grades,  630 

various  constructions,  394. 

theoretical  action,  398,  399. 
Braking  pull,  399. 
Break  in  wiring,  316. 
Bridge,  def.,  256. 
British  thermal  unit,  170. 
Brock  carburetter,  243. 
Brush  planetary  transmission,  390. 
ills.,  391. 

runabout,  ills.,  613. 
Buffing  support,  101 
Burner,  Forg,  510. 

ills..  510. 

Lane,  ills..  506. 

regulator  qaaoline.  des.  and  ills..  50& 

Stanley,  ifla.,  310. 

White,  511. 

ills.,  511. 

Burners,  gasoline,  504,  508. 
By  pass  valves,  513. 
By  pass  valve,  operating,  514. 

c 

Cadillac  transmission  gear,  357. 

variable  valve  lift,  345. 
Cab  with  rear  wheel  steering,  ills.,  66. 
Calculating  by  mean  ordinate,  148. 
Calorific  value  of  fuels,  199. 
Calorific  values,  determination  of,  190. 
Cameron  air  cooled  engine,  193. 
Carbon,  effect  of,  450. 

methods  of  removing,  450. 
Carbonization,  too  rich  mixture,  450. 

prevention  of,  450. 
Carbonized  cylinders,  449. 
Carburetter,  152. 

action  in  cold  weather,  250. 

adjustment  of,  236-242. 

alcohol-gasoline,  ills.,  252. 

Brock,  243. 

dashboard  control,  ills.,  230. 

Duryea,  216. 

ebullition  type,  206. 

essential  principles,  232-235. 

extra  air  port,  245. 

failure  to  start,  432. 

faulty  action  of,  441. 

faulty  adjustment,  416. 

611ing,  418. 


INDEX. 


649 


Carburetter — Continued. 

filtering  type,  206. 

freezing  in,  250. 

freezing  of,  445. 

functions  of,  205-206. 

heating  for,  226. 

Holley,  229. 

ills,  of  early  type,  205. 

jacketed,  226,  227. 

Kingston,  231. 

Krebs,  234. 

Marvel,  251. 

Petrie,  ills.,  237. 

principles,  207. 

proper  sue  important,  234,  235,  236. 

puddle,  206,  228. 

rudimentary  form  of  sprayer,  207-208. 

Schebler,  225. 

selecting  a,  232. 

should  not  be  too  small,  227. 

sprayer  type,  206. 

sticky  valve,  444. 

Stromberg,  244. 

surface,  206,  228. 

theory,  220. 

too  large,  235. 

too  small,  227. 

troubles,  245-251. 

venturi,  230-232. 

water  in,  445. 

Willet,  233. 

Win  ton,  219. 
Carburetters,  205-254. 

and  carburetting,  205. 
Carburetting,  205-254. 

in  cold  weather,  423. 

Care  and  operation  of  storage  batteries,  581. 
Care  of  tires.  126. 

Cannstadt-Daimler  transmission,  382,  383. 
Carriage,  three  wheel,  advantage  of,  68,  69. 
Cars  passing  in  opposite  directions,  diagram, 

628. 

Causes  of  back  firing,  430. 
Causes  of  unbalanced  engine  motion,  323. 
Caution  signs,  American  Motor  League,  634. 
Cell,  def.,  257. 

dry,  258,  260,  261. 
Cells,  dry,  439. 

how  connected,  258. 
primary,  258-261. 

secondary,  258,  261,  263. 

storage,  439. 
Center  of  gravity,  51. 

and  wheel  base,  51. 
why  important.  51,  53. 


Centrifugal  governor,  347. 

Chain  and  sprocket  drive,  ills.,  25. 

Chain  drive,  for  electric  truck,  ills.,  557. 

motor  cycle,  462,  463. 

where  advantageous,  30. 
Chain  driving,  operation  of,  28. 

diagrams,  29. 
Chain,  pitch  of,  31. 

ills.,  31. 
Chains,  adjustment  of,  33. 

block,  27. 

care  of,  32. 

cleaning  of,  33. 

driving,  des.  and  use,  27. 

elongated  link,  32. 

looseness  of,  33. 

roller,  27. 

strength  of,  27,  28. 
Chamber,  float,  210. 

mixing,  221-223. 

receiving,  210. 
Changing  to  high  speed,  623. 

to  second  speed,  621. 
Characteristic  side  lever  control,  616. 
Charge,  fuel,  proportions  of,  206.  • 

volume,  variation  of,  342. 
Charles'  law,  140. 
Chassis  and  springs,  69. 

Riker,  25. 
Church's  coach,  ills.,  10. 

use  of  spring  wheels,  12. 
Circuit,  grounded,  def.,  256. 

low  tension,  elements  of,  276. 

make  and  break,  275. 

metallic,  def.,  256. 

short,  def.,  256. 
City  driving,  629. 
Clash  gear  transmission,  357. 
Cleaning  parts,  637. 
Clearance,  cylinder,  149. 

percentage  of,  166. 

spherical,  186-187. 
Clerk,  Dugald,  experiments  on  compression, 

169. 

Clincher  tires,  ills.,  116. 
Clubbe  and  Southey  hub,  45,  47. 
Clutch,  cone,  358. 

des.,  365. 

Clutches  and  transmissions,  355. 
Clutches,  compression  disc,  361. 

cone,  358. 

drum  and  band,  361. 
expanding  ring,  361. 
multiple  disc,  359,  360. 
requirements,  357,  363. 


650 


INDEX. 


Clutches — Continued. 

troubles,  359. 

types,  356. 

Coal  gas,  figures  for,  172. 
Coaster  brake,  des.  and  ills.,  466. 
Cock,  blow  off,  522. 
Coil,  adjustment  of,  436. 

box,  618. 

care  of,  437. 

defects  in  interior,  436,  437. 

des.,  437. 

induction,  256. 

interior  of,  failure  to  start,  432. 

ills.,  437 

must  be  suitable,  437. 
Coils,  318. 

non-vibrator,  281. 

various,  for  ignition  systems,  297. 

vibrator,  281-285. 
Coil,  vibrator,  failure  to  start,  432. 
Columbia,  electric  vehicle  controlling  appara- 
tus, diagram,  596. 

transmission,   des.   and  ills.,  357,  384, 

385,  386. 
Combustion;  conditions  of,  171. 

space,  soot  deposits,  431. 
Commutator,  office  of,  568. 
Comparison  of  tires,  113. 
Compensating  gear,  16. 

spring,  Olds,  88. 

De  Dion,  88. 

Composite  gas  engine  cards,  350. 
Compound  gas  engine,  181-182. 
Compounding  steam  engine,  482-484. 
Compound  motors,  567. 

spring,  Winton's,  85. 

steam  engines,  484. 
Compression  and  expansion,  163-169. 
Compression  disc  clutches,  356,  361. 
Compression,  high,  efficiency  of,  168. 

operation  of,  156. 

pressure,  166-168. 

ratio  of,  165. 

temperature,  166-168. 

troubles,  low,  448-449. 
Concentric  float  chamber,  212. 
Condenser,  Lane,  535,  536,  537. 
ills.,  536. 

of  vibrator  coil,  283. 
Conditions  of  gas  engine  efficiency,  171. 

of  operation,  measuring  the,  165. 
Conductors,  def.,  255. 
Cone  clutch,  efficiency  of,  358. 

ills.,  366. 

des.,  356,  358. 


Con*  clutch— Continued. 

defects,  359,  361. 

mounting,  ills.,  366. 

Peerless  car,  356. 

Pope-Toledo,  356. 

replacing  leather,  639. 
Connection  of  cells,  258. 
Considerations  in  spring  design,  74. 
Constricting  band  brake,  diagrams,  397. 
Construction  of  springs,  69. 
Contact  breaker,  281,  289,  290. 
Contact  maker,  281. 

Atwater-Kent  system,  313. 

ills.,  283. 
Control.  610. 

and  dashboard  appliances,  ills.,  610 

Vinot  motor,  ills.,  423. 
Control  of  engines,  340. 

construction  of,  607. 

Controller  connections,  for  electric  vehicles, 
603. 

four  unit,  one  motor,  diagram,  604. 

of  electric  vehicle,  599,  606. 

varieties  of,  608. 

Waverly,  603. 
Cooling  system,  Locomobile,  des.  and  ills.,  418- 

motor  cycle,  454. 

Copper  in  boiler  construction,  489. 
Cork  inserts  in  clutches,  365,  366. 
Correct  ignition  tune,  350. 
Counter  current,  274. 
Country  driving,  634. 
Cracking  of  tire  walls,  122. 
Crank,  gas  engine,  153. 
Cranking,  250. 

precautions,  427-428 

right  way,  ills.,  427. 

wrong  way,  ills.,  427. 
Crank,  use  of  in  starting,  234. 
Cross  compound  engine,  diagram,  482. 
Crossing  railroad  tracks,  632. 
Crossley  engine,  169,  181. 
Cugnot,  his  motor  vehicle,  1,  2 

ills.,  2. 
Current,  alternating,  def.,  256. 

counter,  274. 

direct,  def.,  256. 

electric,  why  useful,  256. 

failure  to  start,  432. 

high  tension,  256. 

how  produced,  264,  265. 

induced,  257. 

low  tension,  256. 

primary,  def.,  256. 


INDEX. 


651 


Currents,  def.,  255. 

Current,  secondary,  def.,  256. 

Curve  of  expansion,  139. 

variations  of,  175. 
Cut  off,  of  steam,  471. 
Cut  out  mufflers,  179-180. 
Cycle,  gas  engine,  146-154. 

steam  engine,  145. 
Cylinder,  air  cooling  devices,  191-196. 

clearance,  149. 

cooling  by  air,  191-196. 

cooling,  theory  of,  184. 

failure,  testing  for,  446,  447. 

gas  engine,  149. 

knocking  in,  322. 

multiple,  tests  of,  333-336. 
Cylinders,  air  cooling  for,  183. 

deposit  of  carbon  in,  450. 

water  cooling  for,  183-190. 
Cylinder  walls,  overheating,  431. 


Daimler,  Gottlieb,  2,  3. 

driving  differential,  94. 

engine,  326. 

governor,  340,  341,  342. 

his  first  engine,  2. 

transmission  gear,  357,  358. 

use  of  air  cooled  cylinder,  192. 
Dance,  Sir  Charles,  connection  with  Gurney, 

4,  5,  7. 

Darracq,  use  of  air  cooled  cylinder,  191. 
Data  on  compression  pressure,  168. 
Dayton  burner,  508,  509. 
ill.,  503. 

starting  device,  509. 

Dead  centers,  absence  of,  in  steam  cars,  468. 
Decauville  transmission  gear,  357,  384,  385. 

use  of  air  cooled  cylinder,  191. 
De  Dion  and  Bouton,  compensating  spring,  88. 

engine,  324,  326,  327. 

jointed  axle,  94. 

mention  of,  3. 

rear  axle,  ills.,  41. 

spring  compensation,  87. 
Defective  battery,  439. 

coil,  438. 

primary  wiring,  438. 

timing  device,  438. 
Defective  fuel  mixture,  442. 
Defective  generator,  440. 
Defective  mixture,  misfiring,  444,  445. 

after  firing,  445. 
Defective  spark  plugs,  432. 
Deflection  of  springs.  78. 


Delivered  horse  power,  200. 

Denatured  alcohol,  252. 

Determining  calorific  values  for  fuels,  199. 

Device  for  testing  ignition  advance,  ills.,  319 

Diagram,  engine  performance,  334. 

factor,  480. 

flattening  of  tires,  114. 

gas  engine  valves,  152. 

gravity  water  circulation,  184. 

indicator,  reading  of,  147,  148. 

power  effect,  350. 

spark  timing,  350. 

steam  engine,  147. 

steam  engine  cycle,  145. 

thread  layers  in  tires,  111. 
Diaphragm  feed,  218. 
Dielectric,  def.,  257. 

Difference  between   dynamo   and   magneto, 
diagram,  264. 

of  potential,  def.,  255. 
Differential  gear,  16. 
ills.,  17,  18. 

hub,  Hiker,  19. 

universal  joint,  ills.,  22. 
Difficulty  in  starting,  447,  448. 

carburetter  and  spark  adjustments,  447. 

carburetter  obstruction,  447. 

heated  bearings,  448. 

lost  compression,  448. 

new  parts,  448. 

too  weak  suction,  447. 
Dimension  of  pneumatic  tires,  12ft. 
Dimensions  of  wheels,  95. 
Direct  current,  def.,  256. 
Disc  clutches,  356,  361. 
Disc  feed,  217. 
Dished  wheels,  94. 
Dishing  of  wheels,  52. 

advantages  of,  92-94. 
Distance  rod,  81. 

Distributer,  281,  290,  291,  292,  318. 
Divided  axle  shaft,  disadvantages  of,  20,  21. 
Double  chain,  and  bevel  drives,  30. 

drive,  26. 

ills.,  24. 

Double  ignition,  four  cylinder  wiring  diagram, 
321. 

systems,  308,  309. 
Double  tube  tires,  108-109. 

advantages  of,  115. 
Drive,  bevel,  where  desirable,  SO. 

chain  and  sprocket,  ills.,  25. 

chain,  where  desirable,  30. 

description  of,  16. 

double  chain,  ills.,  24. 


652 


INDEX. 


Drive — Continued. 

double  chain,  troubles  with,  26. 

Haynes,  des.,  37. 

Haynes,  ills.,  37. 

jack  shaft  and  separate  wheel,  26. 

motor  cycle,  462,  463. 

Stanley  carriage,  ilia.,  38. 

straight  line,  37. 

synchronous,  272. 

Driving  and  compensating  devices,  16. 
Driving  chains,  ills.,  26,  97. 

operation  of,  28,  29. 

strength  of,  27,  28. 
Driving  devices,  unusual,  63. 
Driving,  front  wheel,  63,  64. 

gear,  gas  engines,  153. 

gear,  types,  23,  24. 
Draining  jackets,  426. 
Drum  and  band  brake,  ills.,  390. 

clutches,  356,  361. 
Dry  cells,  258,  260,  261,  439. 
Dual  ignition,  Bosch  system,  306. 

wiring  diagram,  300. 
Dunlop  tire,  117. 

duplex  gauge,  519. 

plugs,  292,  294,  295. 
Duryea,  Chas.  E.,  342,  343,  356. 

advocates  three  wheel  carriage,  69. 

carburetter,  216. 

comparison  of  tires,  113. 

engine,  330. 

explanation  of  skidding,  54,  55. 

inclined  pivot,  44. 

on  wood  wheels,  94. 

transmission  gear,  357. 
Dynamic  electricity,  559. 
Dynamics  in  steering,  diagram,  65. 
Dynamo,  264-266. 
Dynamo    and   motor,    operative    conditions, 

diagram,  572. 
Dynamo,  diagram,  566. 

governor  of,  why  needed,  266. 

principles  of,  264,  265,  266. 
Dynamos,  265. 
Dynamos  and  magnetos,  265. 
Dynamos  and  motors,  565. 

essential  parts,  565. 
Dynamo,  typical  form  of,  ills.,  567. 


Eccentric,  diagram,  468. 

gear,  des.  and  ills.,  470,  473. 
Economizer,  Gillett- Lehman,  248. 
Edge,  S.  F.t  333-336. 

torque  diagrams,  335. 


Efficiency,  fuel  consumption,  197. 

of  cone  clutches,  358,  359. 

of  gas  engines,  conditions  of,  171. 

mechanical,  170. 

ratio  of,  170. 
Eisemann   high    tension   magneto,   diagram, 

284. 
Eisemann  magneto,  309. 

ills.,  270. 

Elasticity  of  springs,  78. 
Electrical  horse  power,  562. 

measurements,  units  of,  560. 

terms,  255,  256. 
Electric  and  gasoline  trucks,  comparison  of, 

557. 

Electric  current,  why  useful,  256. 
Electricity,  255,  559. 

explanation  of  principles,  255,  256. 

how  produced,  257. 

by  dynamo,  258,  264. 
by  magneto,  258,  264. 

kinds  of,  559. 

meters,  563. 

used  for  ignition,  255. 

Electric  motors,  arrangement  of  batteries  and 
parts,  596. 

drive,  555. 

position  of,  555. 

varying  speed  and  power,  595. 

varying  the  circuits,  595. 
Electric  motor  troubles,  568. 

common,  diagram,  571. 

improper  connections,  570. 

short  circuits,  570. 

two  motor  troubles,  573. 
Electric  truck  chain  drive,  ills.,  557. 

trucks,  556. 
Electric  Vehicle  Co.,  heavy  wagon  chassis, 

ills.,  607. 
Electric  vehicles,  555. 

advantages  of,  135. 

circuit  arrangements,  603. 

circuit  changing,  597. 

circuits,  600. 

controller  connections,  diagram,  603. 

controller  of,  606. 

four  battery,  one  motor  circuit,  602. 

four  battery,   two  motor  circuit,   dia- 
gram, 602. 

light,  556. 

one  battery  unit  circuit,  diagram,  600. 

principal  types,  555. 
Electrodes,  def.,  257. 
Electrolyte,  how  to  prepare,  261. 

specific  gravity  of,  263. 


INDEX. 


<6S 


Electro-magnet,  258. 

Elements  of  a  vehicle  engine.  152. 

Elliptical  spring,  des.,  72. 

Elwell-Parker  motor  generator  act,  ills.,  580. 

Emery  paper,  limitations,  440. 

Engine,  Adams-Farwell,  ills.,  422. 

before  starting,  416. 
Engine,  Cameron,  193. 
Engine,  Daimler,  326. 

De  Dion  and  Bouton,  324,  326,  827. 

dimensions  in  power  estimates,  201 

does  not  start,  320. 

Duryea,  330. 

failures,   testing  for  missing  cylinder, 
446. 

Ford,  showing  oQ  leads,  ills.,  411. 

four  cylinder,  328,  831. 

Fritscher-IIoudry,  194. 190. 

six  cylinder,  332. 

Olds,  332. 
Engine,  gas,  Atkinson,  ISO,  184. 

balancing,  323-339. 

compound,  181. 

Crossley,  181. 184.  185. 

governing  and  control.  84O-BSi» 

Griffin,  184 

operation  of,  415-450. 

parts  of,  149-153. 
Engine,  careless  management.  41ft. 

locomobile,  347,  348. 

Gobron-Brillie,  827. 

ignorant,  416. 

Maxwell,  329, 

misfires,  320. 

misfires  and  stops,  320. 

Mitchell,  325. 

motor  cycle,  453,  454. 
ills.,  453,  454. 

multiple  cylinder,  330, 

Hiker,  ills,  of  oil  feed,  etc.,  412. 

runs  fitfully,  320. 

runs  with  switch  open,  320. 

Simms,  191. 

Starting,  418. 

starting  in  winter  time,  423. 

suddenly  stops,  320. 

three  cylinder,  329. 

Toledo,  349. 

unsatisfactory  working,  320-322. 

rehicle,  essential  parts,  152,  153. 
Examples  of  carburetter  design,  diagrams, 
238. 

of  throttle  design,  diagram*.  238. 
Exhaust,  colors  in.  241,  242. 
Exhmuat  losses.  178-179. 


Exhaust  losses— Continued. 

prevention  of,  178. 

theory  of.  175-176. 
Exhaust  of  gas  engine.  175-182. 

reducing  smoke  in,  443. 

unpleasant  odor  from,  442. 
Exide  storage  battery.  583. 
flls..  683. 

storage  cell.  583. 

ills.,  583. 

Expanding  ring  clutches,  356,  361. 
Expansion  and  compression,  163-169. 
Expansion,  curve  of,  139. 

in  gas  engine,  ratio  of,  175, 170. 
Experimental  figures  for  heat  losses.  198. 
Explanatory  diagram  of  skidding,  55. 
Explosion,  correct  time  for,  350,  361. 

pressure,  200. 

theory  of,  850,  351. 
Bzplosions  in  muffler,  823. 

weak,  251. 
Extra  sir  port  on  carburetter,  948. 


Fabric  tires,  109. 

failure  to  start,  causes  of.  431-447. 

Fame  plates,  579. 

Faur.te's  crank  and  cycle.  331.  332,  837-330 

Faurote's  valre  timing  diagram,  837. 

Feed,  diaphragm,  218. 

disc,  21*. 

Feeders,  boiler.  618. 
Peed,  float,  211,  212. 
Field  magnet,  258. 
Field,  magnetic,  257. 

windings,  current  direction,  dlngi-mim. 

660. 

Fire  point.  171-172. 
Firing  charge,  early  devices  for,  255. 
Fisk  tire,  117. 

Flash  boiler,  Serpollet's,  497. 
Flash  boilers  in  general,  499. 

seamless  steel  tubing  for,  502. 
Flash  generator,  Serpollet's,  3. 
Flash  point,  171-172. 
Flash  steam  generation,  540,  544. 
Flattening  of  tires,  diagram  of,  114. 
Float,  213-216. 
Float  chamber,  210. 

concentric,  212. 

inclination  of,  212. 
Float,  early  form  of,  209,  210. 
Float  feed,  principles  of,  211,  213. 

simple  form  of,  ills.,  209. 

weight  adjustment,  ilk.,  211. 


654 


INDEX. 


Float  feed — Continued. 

with  spring  adjustment,  ills.,  210. 
Float,  leaky,  247. 
Float  pin,  418. 
Float  point,  214. 
Flooding  of  carburetter,  247-249. 
Fly-wheel,  gas  engine,  153. 
Foot  whistle  control,  618. 
Forced  circulation  of  oil  necessary,  414 
Force  feed  lubricator,  409. 
ills.  409. 

oiler,  410. 

ills.,  410. 

Force,  lines  of,  264. 
Ford  engine,  showing  oil  leads,  ills.,  411. 

ignition  device,  ills.,  273. 
Forg  generator  and  burner,  des.  and  ills.,  510. 
Forma  of  volt-ammeters,  563. 
Formula,  gas  engine  wrist  pin,  150. 

brake  horse  power,  204. 
Forney,  M.  N.,  101. 
Fouling,  preventives,  432. 
Four-cycle  gas  engine,  154-157.  417. 
ills.,  417. 

valve  gear,  des.  and  ills.,  441. 
Four-cylinder  engine,  331. 
Four-cylinders,  failure  of  one,  448,  447. 
Four-cylinder  wiring  diagram,  321. 
Pour  speed  selective  transmission,  diagram. 

374. 
P.  N.  four-cylinder  motor  cycle  engine,  454. 

motor  cycle  shaft  drive,  463. 
Frame,  Holdcn.  452. 

motor  cycle,  452. 

pedestal,  452. 

Wolfmuller  and  Lawson,  452. 
Franklin  air  cooling  system,  195. 
Freezing  in  carburetter,  250. 

precautions,  424. 
Friction  disc  clutch,  ills.,  362. 

transmissions,  358,  361. 
Friction  drive,  Pittsburgh  truck,  ills..  38. 
Fritscher-Houdry  engine,  ills.,  194. 
Front  wheel  driving,  63. 

useless  for  hill  climbing,  64. 
Fuels,  calorific  value  of,  199. 
Fuel  charge,  proportions,  206. 
Fuel  combustion,  conditions  of,  171. 
Fuel  consumption,  ratio  to  efficiency,  197. 

connections,  Lane,  533. 

feed  regulator,  507. 

ills.,  507. 
Fuel  mixture,  defective,  442,  443. 

defective,  cause  of,  173. 

effect  of  varying,  172. 


Fuel  mixture — Continued. 

how  to  test,  444. 

proportions  of,  172. 

theory  of,  171. 

throttling,  349. 

troubles  with,  416. 

variation  of,  340. 
Fuel  regulator,  automatic,  505. 

Ofeldt,  ills.,  517. 
Fuel,  use  of  alcohol,  252-254. 
Fusible  plug,  boiler,  532. 


G.  and  A.  carburetter,  222. 

ills.,  222. 

Gas  and  steam  engines  compared,  355. 
Gas  consumption  per  horse  power,  185. 
Gas  engine,  Atkinson,  180. 

cycle,  146,  154. 

conditions  of  efficiency,  171. 

cylinder,  149. 

cylinder,  section  of,  186. 

efficiency  of,  170. 

four-cycle,  154-157. 

four-cycle,  diagram,  155. 

indicator  cards,  146,  173. 

parts  of,  149-153. 

pistons,  149. 

two-cycle.  158-162. 
Gas  engine,  two-cycle,  advantages,  159. 

diagram,  159,  160. 

disadvantages,  160. 

essentials  of,  159,  160. 

exhaust  of,  160,  161,  162,  175-182. 

operation  of,  158. 

Gases,  pressure  and  temperature  of,  136. 
Gasoline  burners,  des.,  508. 

ills.,  504. 

mixing  tube,  505. 

regulator  ills,  508. 
Gasoline-electric  vehicles,  557. 
Gasoline,    circulation    of    through    float 
chamber,  214. 

comparison  with  alcohol,  254. 
Gasoune  engines,  balancing,  323-339. 
Gasoline  engine,  governing  and  control,  34> 

353. 

Gasoline  engines,  operation  of,  415-450. 
Gasoline,  impure,  249. 

leaks,  246. 

low  grade,  249,  445. 

no  flow  of,  247. 

poor,  416. 

properties  of,  205. 

required  before  starting,  416. 


INDEX. 


655 


Gasoline — Continued. 
stale,  249,  445,  446. 
storing  and  feeding,  505. 
tank,  ills.,  418. 
tank,  Lane,  533. 
testing  and  straining,  416. 
testing  quality,  249. 
vehicles,  advantages  of,  134. 
vaporization  of,  220. 
water  in,  249. 

Gas  pressure  and  volume,  law  of,  137-140. 
Gauge,  duplex,  519. 

ills.,  519. 

Gay  Lussac's  Law,  140. 
Gear,  balance,  16,  17. 
compensating,  16. 
differential,  16. 
necessity  for,  1. 
Gears  bevel,  17.  19,  35. 

ills.,  18. 

differential,  principles  of,  18. 
Gear,  differential,  ills.,  17. 

driving,  types,  23,  24. 
Gearless  planetary  transmission,  364,  365. 

ills.,  364. 

Gears,  engagement  of,  626. 
noise  or  growl  of,  626. 
Gear  shifting,  625. 
on  a  hill,  628. 
with  progressive  type,  627. 
with  selective  type,  627. 
Gears,  spur,  des.  and  ills.,  19,  20. 
Gear,  steering,  ills..  61. 
Gear,  transmission,  forms  of,  357. 
General  Electric  motor,  for  light  vehicles,  574. 
ills.,  569,  573. 
rectifier,  594. 
Generator,  defective,  440. 
flash,  Serpollet's,  3. 
Forg,  des.  and  ills.,  510. 
Generators,  mechanical,  264. 
Generator  valve,  246. 
Generator,  White,  511,  512. 
diagram,  501. 
ills.,  511. 

Geneva  boiler,  495. 
Gillett-Lehman  economizer,  248. 
Glazing,  440. 
Gobron-Brillie  engine,  327. 

steering  apparatus,  61,  62. 
Goggles,  636. 
Goodyear  tire,  117. 
Gould  storage  battery,  positive  plate,  ills., 

580. 
negative  plate,  ill*.,  580. 


Gould  storage  battery— ConttoueO. 

cell,  ills.,  578. 

plate,  576. 
Governing,  devices  for,  340. 

of  engines,  340. 

two-cycle  engine,  162. 

varying  charge  volume,  342. 
Governor,  centrifugal,  347. 

Daimler,  340. 
ills.,  341. 

of  dynamo,  why  needed,  260. 

hit  and  miss,  340. 

pneumatic,  340. 

Riker,  348. 

spark  and  throttle,  35S. 

Winton,  340,  343. 
Graphite,  limitations,  409. 

use  as  lubricant,  409. 
Gravity,  center  of,  51. 

water  circulation,  diagram  of,  ISA. 
Grinding  valves,  ills.,  425. 
Grounded  circuit,  def.,  256. 
Gurney,  Goldsworth,  4. 

coaches,  4,  5,  7. 
ills.,  5. 

H 

Half  elliptic  spring,  ills.,  73. 
Hammer  vibrator,  ills.,  285. 
Hancock,  Walter,  7,  92. 

boiler,  8,  9. 
ills.,  8. 

coaches,  7,  8. 
ills.,  8. 

wedge  wheel,  des.,  9. 
ills.,  9 

wheel,  92. 

Hand  control,  243-245. 
Hand  feed  pump  for  high  pressure,  515. 

for  medium  pressure,  515. 
Handling  a  gasoline  car,  609. 
Haynes-Apperson  pivot  axle,  45. 

transmission,  357,  388. 

ills.,  388. 
Haynes,  double  yoke  pivot,  44, 

drive,  36,  37. 

spur  gear,  ills.,  40. 
Heat  economy,  185,  186,  187. 

rate  of  absorption,  187. 

rate  of  water  circulation,  188. 

temperature  of  water,  187,  189. 
Heat  engines,  operative  conditions  of,  137. 

theory  of,  136. 

Heat,  how  caused  by  electric  current,  25*. 
Heating  for  carburetters,  226. 


656 


INDEX. 


Heat,  mechanical  equivalent  of,  197,  198. 

units,  equivalent  in  horse  power,  200. 

units,  relation  to  temperature  of  steam, 

142. 

Herring  bone  reduction  gears,  ills.,  568. 
Herschmann  spring  frame,  83,  84. 
High  compression,  efficiency  of,  168. 

figures,  168. 

High  speed,  changing  to,  623. 
High  speeds,  fuel  economy  of,  186. 
High  tension,  current,  256. 

ignition,  280. 

ignition  circuits,  296,  297. 

magneto,  diagram,  269. 

magnetos,  267,  268,  270,  271,  297. 

principles,  diagram,  298. 

spark,  280. 

wiring  diagram,  298. 
Hill  climbing  and  steering,  58. 
Hill,  suspension  spring,  ills,  and  des.,  83. 

governors,  340-342. 

ills.,  342. 

Holley  carburetter,  229. 
Holsiuan  high-wheeled  gasoline  surrey,  ills., 

611. 
Horse  power,  185. 

brake,  203-204. 

delivered,  200. 

electrical,  562. 

equivalent  in  heat  units,  200. 

indicated,  202. 

Hub,  Clubbe  and  Southey,  47. 
Hub,  differential,  Riker,  19. 

Rikcr's,  44-46. 

Clubbe  and  Southey,  45. 
Hurtu  electric  cabs,  63,  64. 

motor  steering  wheels  of,  ilk.,  64. 


Igniters,  320. 

Acme,  313,  314. 

American,  314. 

failure  to  work,  320. 

low  tension,  434. 

low  tension,  ills.,  434. 

Perfex,  314. 

Pittsfield,  313,  314. 

Igniting  devices,  various,  297,  310,  311. 
Ignition,  157,  255-322. 

apparatus,  disorders  in,  416. 

circuits,  high  tension,  296,  297. 

control,  340. 

cut  out  plug.  618. 

early  devices  for,  255. 

high  tension,  280,  281. 


Ignition — Continued. 

magneto,  305. 

synchronous,  297,  302-305. 

systems,  273-314. 

systems,  double,  308,  309. 

testing,  315,  319. 

time  of,  157,  350. 

timing  of,  340. 

troubles,  315-322. 

varying  point  of,  350. 

with  coil  spark  plugs,  307. 

with  inductor  magneto,  280. 

with  plain  coil,  299. 

with  master  vibrator,  301,  302. 

with  mechanical  vibrator,  299. 

with  vibrator  coils,  300. 
Inclination  of  float  chamber,  212. 
Indian  coaster  brake,  ills.,  466. 
Indian  motor  cycle  cylinder  head  and  valves, 
455. 

engine  valve  gear,  456. 

valve  gear,  455,  456. 
Indicated  horse  power,  202. 
Indicator  card,  350. 

Atkinson,  180. 

Indicator  cards,  gas  engine,  173. 
Indicator  diagram,  144-148. 
Induced  current,  257. 
Individual  clutch  transmission,  357. 
Induction  coil,  256. 

secondary,  281. 

Induction  coils,  wiring  diagrams,  286. 
Induction,  explanation  of,  257. 
Inductor  magnetos,  266,  280. 
Inserts,  cork,  in  clutches,  365,  366. 
Insulation,  def.,  256. 
Invisible  lines  of  ofrce,  264. 
Iridium,  why  used,  274. 
Irreversible  steering,  58. 


Jackets,  draining  of,  426. 
Jacket  water,  efficiency  of,  184. 

freezing  of,  424. 

rate  and  quantity.  184. 
Jack  shaft  and  separate  wheel  drive,  26. 

De  Dion,  40. 

Jacketed  carburetter,  ills.,  226. 
James'  coach,  11. 

ills.,  11. 

Jar  absorbing  devices,  460. 
Jeffrey  Rambler  car,  353. 
Joule's  Law,  143. 
Joy  valve  gear,  diagram,  474. 

on  White  engine,  ilia.,  475. 


INDEX. 


657 


Tump  spark,  250. 
ignition,  280. 

diagram.  298. 


Kingston  carburetter.  231. 

Kit  of  tools,  643. 

Klinger  reflex  water  gauge,  ills.,  518. 

Knocking  in  cylinder,  322. 

of  engine,  321. 
Knox-Mercedes  transmission,  des.  and  ilia* 

386,  387. 
Knox  pin  cooled  cylinder,  191. 

transmission  gear,  357« 
Komet  magneto,  271. 
Krebs  carburetter,  234 


Lamp  equipment,  637. 
Lane  air  pressure,  534. 

automatic  by-pass,  535. 

auxiliary  control  system,  638. 

burner,  506,  507. 
ills.,  506. 

by-pass,  535. 
ill<.,  535. 

condenser,  535,  536,  537. 

cycle  of  operation,  539. 

engine,  481. 
ills.,  481. 

fuel  connections,  533. 

gasoline  tank,  533. 

semi-flash  boiler,  ills.,  496. 

eimpling  valve,  481. 

steam  system,  533. 

system,  524. 

water  connections,  534, 

water  indicator.  534,  535. 

water  tank,  534. 
Large  wheels,  troubles  with,  97. 
Law,  Boyle's,  138. 

Charles',  140. 

Gay  Lussac's,  140. 

Joule's,  143. 

of  gas  pressure  and  volume,  137-1401 
Lead,  def.,  256. 
Leaks  of  gasoline.  246. 
Leaky  float,  247. 
Leather  reinforced  tire,  120. 
Lifu  steam  truck,  ills,  of  tire,  101. 
Light  carriage  compound  steam  engines,  484. 
Light  electric  vehicles,  556. 


Line-?  of  force,  264. 
Link  motion,  470,  473. 

diagrams,  471,  473. 

"open"  and  "closed"  rods,  473. 
Liquid  fuels,  503. 
Live  end  of  armature,  267. 
Local  sulphatation,  263. 

Load,  proportions  of  static  and  maximum,  76 
Load,  static,  76. 

maximum,  76. 

ultimate,  76. 
Locomobile,  brakes,  400. 

control  connections,  diagram,  348. 

cooling  system,  des.  and  ilR,  419. 

engine,  347,  348. 

governor,  347. 

igniter,  434. 

ills.,  434. 
Lodestone,  256. 

Long  wheel  base  and  steering,  58. 
Loose  connections,  misfiring,  438. 
Looseness  of  chains,  33. 
Loss  of  power,  322. 

without  misfiring,  448. 
Low  compression  troubles,  448,  449. 
Low  tension,  circuit,  elements  of,  275. 

current,  256. 

igniter,  434. 
ills.,  434. 

Ignition,  273. 

magnetos,  267. 

Low  tension  system,  diagram,  276. 
Lubricant,  use  of  graphite,  409. 
Lubricants,  various  kinds  required,  407 

requirements  of,  407. 
Lubricating  connections,  528. 

oil,  required  before  starting,  416. 

system.  Pierce,  412. 

ills.,  412. 
Lubrication,  407-415. 

before  starting,  421. 

how  often,  414. 

instructions  for,  413. 

motor  cycle,  454,  465,  466. 

points  on  413. 

splash  system,  455. 
Lubrication  systems,  421. 

gravity,  421. 

positive,  421. 

pressure,  421. 

splash,  421. 

Winton,  420. 
Lubricator,  force  feed,  408. 

ills.,  409. 


658 


INDEX. 


M 

Maceroni  and  Squire,  6. 

MacLachlan  single  acting  compound  engine, 

ills.,  480. 

Magnetic,  circuit,  diagram,  278. 
field,  257. 

make  and  break  spark  plugs,  292. 
poles,  256,  257. 
spark  plugs,  277-279. 
Magnetism,  explanation  of,  256,  257. 
Magneto,  264-272. 
ignition,  305. 
inductor,  280. 
principles  of,  264,  266. 
varietiea  of,  266. 
Remy  high  tension,  297. 
Make  and  break  circuit,  275. 
spark,  256. 
system,  diagram,  276. 
Management  of  engines,  416. 
Marvel  carburetter,  ills.,  251. 
Marmon  clutch,  363. 

support,  des.  and  ills.,  68. 
Master  vibrator  coil,  301,  302. 
Matheson  car,  ills,  of  wheel,  52. 
multiple  disc  clutch,  360. 
Maximum  load,  76. 

proportion  to  static,  76,  77. 
Maxwell  double  opposed  engine,  329. 

transmission  lever,  ills.,  615. 
Maybach  carburetter,  205. 
Mean  effective  pressure,  148,  202. 
Mean  ordinate,  calculating  by,  148. 
Mechanical  efficiency  of  gas  engine,  170. 
equivalent  of  heat,  197,  198. 
generators,  264. 
vibrator  ignition,  299. 
ills.,  288. 

Mercedes  springs,  84. 
Mercury  arc  rectifier,  593. 
Meshing  spur  transmission,  357. 
Metallic  circuit,  def.,  256. 
Meters,  electricity,  563. 

index  scales  of,  diagram,  563. 
Methods  of  producing  electricity,  257. 
Mica,  use  as  insulating  material,  294. 
Mineral  oils,  where  and  why  needed,  412. 

why  necessary,  407. 
Misfiring,  250,  429. 

defective  coil,  438. 

defective  mixture,  444. 

faulty  vibrator  adjustment,  436. 

of  engine,  320,  321. 

short  circuits,  433. 

weak  battery,  440 


Mitchell  four-cylinder  engine,  325. 
Mixing  chamber,  221-223. 
Mixture,  223,  224. 

faintly  blue  flame,  444. 
proper  action  of,  444. 
should  vary  with  conditions,  224. 
varying,  347. 
yellow  flame,  444. 
Mora,  191.  342,  343. 

engine  governor,  346. 
mention  of,  3. 
spring,  ills.,  71. 
throttling  device,  346. 
use  of  air  cooled  cylinder,  191. 
Motor  carriage  springs,  72. 

wheels,  89-98. 

Motor  cycle,  belt  drive,  ills.,  462. 
brakes,  466. 
cooling  system,  454. 
drive,  462,  463. 
engine,  453   454. 
engine  lubrication,  454. 
engine  position  of,  452. 
engine  twin  cylinder  crank  case,  455. 
framework,  ills.,  452. 
lubrication,  465,  466. 
Motor  cycles,  451-468. 

battery  and  coil  connections,  diagram 

457. 

horse  power  of,  452. 
ignition  and  control,  457. 
jar  absorbing  devices,  460. 
riding,  465. 

spark  and  valve  timing  diagrams,  461. 
Starting,  464. 
stopping,  466. 
Motor  cycle,  Thiem,  459. 

ills.,  459. 

with  belt  drive,  ills.,  451. 
wheels,  452. 

"V"  twin  cylinder  engine,  ills.,  452. 
Motor,  series,  567. 
Motors,  shunt  and  compound,  567. 
Motor  steering  wheel  of  Hurtu  cabs,  ills.,  64 
Motor  vehicles,  early  history  of,  1,  2. 
early  use  of  steam,  2. 
modern,  motive  power,  13. 
requirements  for,  1. 
supports,  67. 
Muffler,  429,  430. 

back  pressure  in,  178. 
calculation  of  dimensions,  177,  178 
cubic  content,  177. 
cut  out,  179,  180,  618. 
exhaust,  177,  178. 


INDEX. 


659 


Muffler — Continues. 

explosions,  322. 

ills.,  429. 

losses,  178. 

simplex,  ills.,  430. 
Multiple,  connection,  258. 

cylinder  engines,  330. 

cylinder  tests,  333-338. 

diagram,  259. 

disc  clutch,  359,  360. 

nozzles,  219. 
Mushroom  valves,  151. 

N 

Negative  pole,  257. 
Negotiating  turns,  632. 

greasy  corner,  634. 
Night  driving,  636. 
Non-conductor,  def.,  256 
Non-freezing  solutions.  425.  426. 
Non-vibrator  coil,  281. 

Northern  car,  ills,  of  spring  arrangement  76. 
Nozzle  design  of  carburetter,  ills..  <517. 
Nozzle,  multiple,  219. 

spray,  218. 

N.  S.  U.  motor  cycle  switch  handle,  ilia..  4«tt 
Nut,  traveling,  59,  61. 


Oakland  engine  showing  balancing.  !Ji*..  853. 
Odors,  causes  of,  442. 
Ofeldt,  boiler  ratings,  494. 

compound  engine,  ills,,  479. 

fuel  regulator,  ills.,  517. 

system,  des.  and  ills.,  542. 

table  of  boiler  sizes,  403. 

water  regulator,  ills.,  616. 

water  tube  boiler   (horizontal   drum), 
ills.,  493. 

water  tube  bo>ler  (vertical  drum),  Uls_ 

493. 
O'Gorman,  Mervyn,  133. 

on  steam  carriages,  133. 
Ohm,  255,  560. 
Oil,  different  qualities  of.  421. 

for  lubrication,  421 

forced  circulation  necessary,  414. 

gummy,  424. 

lubricating,    required    before    starting. 
416. 

pump,  408. 
ills.,  408. 

pumps  and  circulation,  414. 
Oiler,  fore*  feed.  des.  and  ills..  410. 


Oiling  before  starting.  431. 

how  often,  414. 
Oils,  animal,  412. 

qualities  of,  410. 

lubricating,    qualities    necessary,    411 
412. 

lubricating,  tests,  410. 

mineral,  where  and  why  needed,  412. 

mineral,  why  necessary,  407. 

organic,  objections  to,  408. 

vegetable,  why  avoided.  412. 
Old*  compensating  spring.  88. 

engine,  crank  shaft,  332. 

transmission  gear,  357. 
One  lever  gridiron  siot  transmission,  357. 

selective  finger  transmission,  357. 

sliding  sleeve  gears,  357. 
Operating  a  car  at  ni^ht,  636. 
Operating  the  brakes,  630. 
Organic  oils,  objection  to,  408. 
Oscillating   type   magneto,   circuit  diagrmt 

279. 
Overhauling  the  car,  637. 


Packard  ring  ciutch,  357. 

spring,  ills.,  72. 

transmission  control,  diagram.  879. 

transmission  gear,  357 
Fanharrl-Levassor,  GO.  191. 

hub  brake,  i  Is.,  890. 

mention  of.  S. 

transmission,  diagram,  877. 

transmission  gear,  357. 

use  ot  air  cooled  cylinder,  191. 
Parallel  connection,  258. 

diagram,  259. 
Parts  of  a  gas  engine.  149. 
Parts  of  driving  circuit,  diagram.  599. 
Passing  a  car.  diagram,  629. 
Pedestal  frame,  ills..  83. 

Rainier,  84. 
Peerless  car,  ills,  of  bevel  drive,  35. 

cone  clutch,  356. 

Ignition  system,  309. 
Petrie  carburetter,  ills.,  237. 
Peugeot  cars,  86. 

mention  of,  3. 

valve  lift,  342. 
Pierce  car,  ills.,  of  bevel  drive,  35. 

engine,  331. 

four-cylinder  engine,  ills.,  331. 

lubricating  system,  ills.,  412. 
Pierce- Racine  rear  axle,  41. 
Pipe,  air  inlet,  247. 


660 


INDEX. 


Piston  construction,  149. 

distributer,  291. 

gaa  engine,  149. 

igniter,  313,  314. 

packing  ring,  151. 

rings,  150,  151. 

Pittsburgh  truck,  ills,  of  drive,  39. 
Pivot,  Duryea's  inclined,  ills.,  44. 

Haynes  double  yoke,  44. 
Plain  bearings  as  rotative  bearings.  402. 
Plain  coil  ignition,  299. 

with  contact  breakers,  297. 

with  master  vibrators,  297. 

with  mechanical  vibrators,  297. 
Plain  vibrator,  284. 
Planetary  transmissions,  357,  361. 

gearless,  365. 
ills.,  364. 

Plate  of  storage  cell,  ills.,  576. 
Platinum,  why  used,  274. 
Plugs,  spark,  292,  295,  297,  307. 
Plunger  feed  pumps,  513,  514. 
Plus  pole,  257. 
Pneumatic  control,  340. 

governor,  Winton's,  343,  344. 

tires,  102,  107-131. 

tires,  absorb  vibration,  75,  77. 

tires,  advantages,  107-108. 

tires,  care  of,  126-128. 

ills,  of  various  mishaps,  130. 

tires,  necessity  for,  1. 

tires,  repair  of,  128,  129. 

tires,  removal  from  wheel,  127-131. 

tires,  troubles  with,  119,  125. 
Point  of  ignition,  varying,  350. 
Points  on  lubrication,  413. 

on  spring  suspension,  80. 
Pole,  magnetic,  256,  257. 

negative,  257. 

north,  257. 

plus,  257. 

south,  257. 
Pope-Toledo  cone  clutch,  356. 

steering  wheel,  ills.,  428. 

transmission,  ills.,  380. 
Poppet  valves,  151. 
Pop  safety  valve,  Ilia.,  521. 
Porcelain,  use  of  as  insulating  material,  294. 
Position  of  valves,  336. 
Positive  inlet  valve,  151,  152. 
Potential,  difference  of,  def.,  255. 
Power  derived  from  heat,  136. 

effect,  diagram,  350. 

efficiency,  185. 

elements  of  a  gas  engine,  197. 


Power — Continued. 

estimates,  elements  in,  201,  202. 

how  applied,  16. 

loss  of,  322,  448. 

output  of  electrical  vehicles,  564. 
Pre-admission,  224. 
Precautions  to  prevent  freezing,  424. 
Pre-ignition,  224,  321,  448. 
Pressure,  absolute,  141. 

and  temperature  of  gases,  136. 

explosion,  200. 

final,  163-164. 

gas,  law  of,  137-140. 

initial,  163-164. 

of  compression.  166-168. 

mean  effective,  202. 

relations  to  temperature,  142,  143. 
Primary  cells,  258-261 

connections,  318. 

current,  def.,  256,  257. 

induction  coil,  274. 

plugs,  292. 

short  circuits,  317. 

spark,  274. 

switch,  318. 

winding,  257. 

wiring,  defects  in,  438. 
Principles  of  electricity,  559. 
Progressive  transmission,  370. 

ills.,  371. 

Propeller  drive,  Haynes,  ills.,  36. 
Propeller  shaft,  care  of,  640. 

transmission,  ills.,  34,  35. 
Prony  brake,  ills.,  203. 
Proportionate  loads,  76. 
Protection  against  skidding,  53. 
Puddle  carburetter,  228,  230. 
Pullman  four-cylinder  car,  637. 
Pump,  hand  feed  for  high  pressures,  515. 

for  medium  pressures,  515. 

plunger,  513. 
ills.,  514. 

oil,  des.  and  ills.,  408. 

troubles,  515. 


Rack  and  traveling  nut,  61. 
Radial  ball  races,  ills.,  403 
Radiator,  cleaning  of,  638. 

dimensions  of,  190. 

filling,  418. 

for  cooling  water,  189,  190. 
Radius  rods,  87. 
Railroad  wheels,  position  in  turning  curve,  48 

turning  arc  of,  46. 


INDEX. 


661 


Rainier  pedestal  frame,  84. 
Rambler  car,  353. 

Rauch  and  Lang  controller,  ills.,  606. 
Ratio  of  compression,  165. 

of  efficiency,  170. 

of  expansion  in  gas  engine,  175. 
Reading  an  indicator  diagram,  147. 
Rear  wheel  steering,  66. 
Receiving  chamber,  210. 
Rectifier,  General  Electric,  594. 

mercury  arc,  593. 
Reduction  of  vibration,  99. 
Regas  air  cooling  system,  194-195. 
Regulation  of  valve  lift,  340. 
Regulator  for  gasoline  burner,  ills.,  508. 

fuel  feed,  ills.,  507. 
Removing  air  tube,  ills.,  129,  131. 

cylinder  castings,  638. 

magneto,  638. 
Remy  high  tension  magneto,  297. 

wiring  diagrams,  297. 
Repair  of  tires,  128. 
Resilience  of  springs,  73. 
Resistance,  255. 

of  springs,  73. 

Resistivity  of  different  metals,  560. 
Return  conductor,  256. 
Rheostat,  use  of,  262. 
Riding  motor  cycles,  465. 
Riker  chassis,  ills.,  25. 

differential  hub,  19. 

engine,  ills,  of  oil  feed,  etc.,  413 

governor,  348. 

hub,  44. 

steering  hub,  ills.,  46. 

transmission  gear,  357. 
Rin£  clutch,  Packard,  357. 

clutches,  356,  361. 
Rings,  piston,  150,  151. 
Road  signals,  630. 
Road  surface  and  tires,  100. 
Roberts'   formula  for  gas  engine  wrist  pin, 

150. 

Rod,  radius,  87. 
Roller  bearings,  ills.,  401-406. 

construction  of,  405,  406. 

chains,  27. 

tube  expander,  ills.,  487. 
Rotating  supports,  401. 

as  sliding  surfaces,  401-402. 
Rotative  bearings  as  plain  bearings,  402. 
Rudimentary  carburetter,  diagram,  207. 
Rubber  tires,  102. 

first  use  of,  11. 

aoMd,  99-118. 


Rubber,  why  used  for  tires,  99,  100. 
Running  a  car  at  night,  636. 
Running  down,  reasons  for,  447-448. 
Running  with  switch  off,  448. 
Russell,  J.  Scott,  11. 


Safety  air  gap,  296. 
Safety  valve,  521,  522. 

for  superheated  steam,  522. 

pop,  521. 

pot,  521. 

Serp.llet,  ills.,  541. 

Sandpaper,  why  preferable  to  emery,  440. 
Sangster  valve,  ills.,  118. 
Scavenging,  advantages  of,  174. 
Schebler  carburetter,  ills.,  225. 
Schrader  valve,  ills.,  118. 
Scroll  bottom  spring,  ills.,  72,  73. 
Seabury  water  gauge,  ills.,  518. 
Seamless  steel  tubing,  502. 
Secondary  cells,  258,  261-263. 

current,  256,  257. 

induction  coil,  281. 

plugs,  292. 

short  circuits,  317. 

spark,  280. 

winding,  257. 

wiring  defects,  433. 
'  wiring,  failure  to  start,  432. 
Second  speed,  to  change  to,  621. 
Selecting  a  carburetter,  232. 
Selective  spur  transmission,  381. 

transmissions,  372. 
Selectors,  616. 

four-speed,  ills.,  617. 

three-speed,  ills.,  617. 
Self-induction,  283. 
Self-starter,  618. 
Semi-elliptical  spring,  72,  73. 
Semi-flash  boilers,  494. 
Series  connection,  258. 

diagram,  259. 
Series  motor,  567. 

Series  multiple  connection,  diagram,  259 
Serpollet's  flash  boiler,  31,  497. 

advantages,  497. 

earliest  form,  ills.,  497. 

heating  surface  per  H.  P.,  497. 

later  form,  498. 

recent  form,  ills.,  499. 

second  form,  ills.,  497. 
Serpollet  system,  540-543. 

fuel  and  water  pumps,  540. 

fuel  and  water  regulation,  543. 


662 


INDEX. 


Serpollet's  system — Continued. 

safety  valve,  ills.,  541. 

single  acting  engine,  477. 

working  pressure,  497. 
Shaft  drive,  motor  cycle,  462,  463. 

ills.,  463 

Shell  boilers,  485. 
Shifting  link,  ills.,  471-473. 

operation  of,  471. 
Shock,  absorber,  ills.,  86,  87. 
Shock  absorbing  devices,  460. 
Shocks,  neutralizing,  96. 
Short  circuit,  256. 
Short  circuits,  317. 

misfiring,  433. 

Shunt  and  compound  motors,  567. 
Shunt  motors,  567. 
Side  flange  tire,  117. 
Side  slipping,  51,  52. 

how  to  avoid,  57. 

Siemans-Halske  electric  motor,  ills.,  569. 
Silencer,  exhaust,  177,  178. 

losses,  178. 
Simms-Bosch  magneto,  316,  317. 

circuit  diagram,  317. 
Simms  cycle  engine,  ills.,  191. 
Simms  fan  cooled  cylinder,  191. 
Simplex  muffler,  ills.,  430. 
Simpling  valves,  White  engine,  ills.,  483-484. 
Single  and  double  tube  tires,  sectional,  ills., 

112. 

Single  coils  with  distributers,  297. 
Single-tube  tires,  108-109,  113 
Single- tube  thread  tires,  110. 
Six-cylinder  engine,  332. 

Winton  engine,  328. 

wiring  diagram  for  double  ignition,  310. 
Si/e  of  carburetter,  234. 
Skidding  and  side  slipping,  51,  52,  53,  635. 
Skidding,  explanatory  diagram,  54,  55. 
Slide  valve,  lap,  469. 

operation  of,  diagram,  468. 

steam  engine,  operation,  469,  470. 
Sliding  spur  transmission  gear,  357. 
Sliding  surfaces,  401. 

as  rotating  supports,  401-402. 
Slow  and  fast  moving  vehicles,  diagram,  635. 
Small  and  large  wheels,  diagram,  96. 
Smoke,  causes  of,  442. 

dark  and  dense  white,  442. 
Smoky  exhaust,  dangers  of,  443. 

how  to  avoid,  443. 
Solid  clincher  tire,  Swinehart,  105,  106. 

rubber  tires,  99-118. 

tires.  102-106. 


Solid  clincher  tire — Continued. 

tires,  durability,  104. 

tires,  method  of  attachment,  ills.,  103. 

structural  requirements,  104. 
Solutions,  non-freezing,  425,  426. 
Span  length  of  springs,  79. 
Spark  adjustment   426. 

after  starting,  431 

Spark  and  throttle  adjustments  before  start- 
ing, 426. 

Spark  and  throttle  governors,  353.  354. 
Spark,  control  of,  623. 

generator,  Atwater-Kent,  311-313. 

high  tension,  280. 
Sparking  pressure,  295. 
Sarking  systems,  derangement,  416. 
Spark  lever,  612. 
Spark,  make  and  break,  256. 
Spark  plugs,  292,  295,  297,  307. 

ills.,  277,  292-295,  320. 

care  of,  295. 

coil,  307. 

defective,  432. 

failure  to  start,  432. 

failure  to  work,  320. 

ground  electrode,  294. 

insulated  electrode,  294. 

insulation  failures,  294. 

insulating  material,  294. 
Spark,  position  when  cranking,  422. 

regulation  and  speed,  351. 

secondary,  280. 

t  lining  and  power  effect,  351. 

timing  for  motor  cycle,  diagram.  461 

timing,  ills.,  461. 
Speed  and  spark  regulation,  351. 
Spherical  clearance,  186-187. 
Splitdorf  master  vibrator  coil,  303. 
Spray  nozzle,  218. 
Spring,  air  valve,  240. 

alignment,  82. 

attachment,  81. 

design,  considerations  affecting,  74. 

frame,  Herschmann,  83. 

suspension,  80,  81. 

suspension,  Truffault,  86. 

three  point  suspended,  ills.,  70, 

wheels,  12. 
Springs,  action  of,  73,  74. 

adjustment  of  weights  on,  77. 

arrangement  of,  77. 

calculating  dimensions,  78t  79,, 

cut  and  try  method,  80. 

deflection  of,  78. 

demands  upon,  77. 


INDEX.  663 

Springs— Continued.  Starting  motor  cycles,  484. 

diagrams  of  strains,  78.  Starting  a  gasoline  car,  619. 

dimensions,  76.  after  cranking,  620. 

elasticity  of,  78.  bad  odors  and  smoke,  442. 

functions  of,  69,  85.  before  cranking.  620. 

half  elliptic,  ills.,  73.  cranking,  234,  620. 

Hill  system  of,  83.  other  operations,  620. 

importance  of  proper  arrangement,  67.  supplies,  619. 

Mercedes,  84.  Static  electricity,  559. 

number  of  plates,  79.  load,  proportion  to  maximum,  76,  77. 

on  motor  carriages,  72.  Steam,  advantages  of,  467. 

placing  of,  77.  and  gas  engines  compared,  355. 

platform,  ills.,  70.  as  a  motive  power,  467. 

requirements  for,  72,  73.  efficiency  for  various  cut  offs,  480. 

resistance  and  resilience  of,  73.  high  pressures,  468,  523. 

scroll  bottom,  ills.,  73.  medium  pressures,  523. 

span  length,  79.  practical  expansive  working,  478. 

stresses  on,  82.  superheated,  468. 

supplementary,  84.  table   of   pressures   and    temperatures 

suspension  of,  80.  141. 

theoretical  considerations,  80.  used  in  early  motor  vehicles,  1,  2. 

three  point,  ills.,  70.  Steam  carriages,  early  types.  1-12. 

Truffault's,  86.  carriage  fuel  feed  regulator,  des.  and 

valve,  152.  ills.,  507. 

varieties  of  leaf,  72.  Steam  engine,  compounding.  482-484. 

Win  ton's,  ills.,  85.  cycle,  diagram,  145,  147. 

working  strength,  79.  diagram  factor,  480. 

Sprocket,  proportions  and  pitch,  30,  31.  heat  losses  in,  480. 

Spur  compensating  gears,  19,  20.  indicator,  144-148. 

drive,  efficiency  of,  39.  piston  of,  478. 

gear.  Haynes,  40.  SerpoDet's  single  acting,  477. 

Spur  gear  transmissions,  38,  39.  slide  valve,  operation,  469,  470. 

Stale  gasoline,  445,  446.  torque  of  two-cylinder.  468. 

Standard  pipe  sizes,  table  of,  236.  Steam,  gauge,  ills.,  520. 

Stanley,  boiler,  ills.,  486.  generation,  flash,  540,  544. 

burner,  ills.,  510.  generator  and  burner,  White,  ills.,  511. 

drive,  ills.,  38.  pressures  for  various  types  of  engine 

engine,  ills.,  472,  476.  523. 

fuel  connections,  525.  system,  Lane,  533. 

lubricating  connections,  528.  systems,  523-532. 

steam  connections,  ills.,  532.  vehicle,  advantages  of,  133,  134. 

steering  wheel,  526.  vehicle,  disadvantages  of,  134. 

superheater,  ills.,  532.  wagon,  Clarkson-Capel,  59. 

system,  fuel  connection,  ills.,  524,  525.  Cugnot's,  1,  2,  4. 

tubes  and  heating  surface,  487.  steel  in  boiler  construction,  489. 

water  and  lubricating  connections,  ills.,  tubular  wheels,  advantages,  90,  91. 

528.  Steering,  and  long  wheel  base,  56. 

water  connections,  527.  angle,  diagram,  49. 

water,  gasoline  and  oil  pumps,  iHs.,  527.  angle,  how  affected,  51. 

water  level,  des.  and  ills.,  529-531.  apparatus,  Gobron-Brillie,  61,  62. 

Starter  box,  Dayton,  509.  arc  of,  45. 

Starting,  details  to  observe,  423.  arms,  ills.,  50. 

Starting,  difficulty  in,  447.  arrangement,  Clarkson-Capel,  59. 

Starting,  failure  of  engine  in,  320.  axles,  arrangement  of,  43-45. 

Starting,  preparations  in  winter,  423.  axles,  theory  of,  43. 


664 


INDEX. 


Steering — Continued, 

by  rear  wheel,  66. 

by  tiller,  danger  of,  65. 

by  wheel,  how  to  hold  wheel,  66. 

by  wheel,  principles  of.  65. 

construction,  48. 

device,  worm  and  sector,  60. 

devices,  unusual,  63. 

diagram,  65. 

gear,  42. 

gear,  ills.,  61. 

irreversible,  58. 

motor  wheel,  64. 

theory  of,  45. 

wheels,  47. 
Steering  wheel,  Pope-Toledo,  428. 

Stanley,  ills.,  526. 

Vinot  motor,  ills.,  423. 

versus  tiller,  58. 
Sticking  from  gummed  oil,  424. 
Stopping,  of  motor  cycles,  466. 

of  engine,  320. 
Storage  batteries,  261-263,  575. 

batteries  used  occasionally,  590. 

capacity  of,  585. 

charge  indications,  584. 

charging  for  first  time,  581. 

charging  period,  new  battery,  582. 

cleaning  jars,  593. 

condensed  rules,  593. 

connections  for  charging,  581. 

current  strength,  582. 

definition  of,  575. 

disconnecting  cells,  592. 

electrolyte,  581. 

Faure  type.  578. 

high  charging  rates,  586. 

imperfect  sulphatation,  584. 

lack  of  capacity,  591. 

old  electrolyte,  584. 

normal  charging  rate,  583 

Plant  type,  577. 

plate  material,  576. 

portable  instruments  used,  582. 

red  scales,  584. 

short  circuiting,  590. 

specific  gravity  of  electrolyte,  582.' 

taking  batteries  out  of  commission,  592. 

theory  of,  575. 
Storage  cells,  439. 

cells,  plate  or  "grid,"  ills..  576 

cells,  typical,  579. 
Straight  line  drive,  37. 
Stresses  on  springs,  82. 
Stromberg  carburetter,  244. 


Structural  conditions.  185. 
Stud  axles,  necessity  for,  ]* 
Sulphatation,  263. 

how  caused,  263, 

local,  263. 

Summers  and  Ogle,  6. 
Supplementary  springs,  84. 
Supplies  required,  416. 
Support,  advantage  of  three  point,  68. 

Marmon,  ills.,  68. 
Surface  carburetter,  228,  230. 
Suspended  wire  wheels,  90. 
Suspension  of  springs,  points  on,  80,  81 
Swinehart  tire,  ills.,  105. 

advantages  of,  106. 

tires,  108. 
Switch  connections,  318. 

handle,  ills.,  460.  . 

primary,  318 
Synchronous  drive,  272. 
Synchronous  ignition,  297,  302-305. 

ignition,  diagram,  304. 


Table  of  standard  pipe  sizes,  236. 
Temperature,  absolute,  140. 

and  volume  of  gases,  140. 

final,  163-164. 

initial,  163-164. 

of  compression,  166-168. 

relations  to  pressure,  142,  143. 
Terms,  electrical,  255,  256. 
Theory,  of  cylinder  cooling,  184. 

of  heat  engines,  136. 

of  steering  axles,  43. 
Thermal  unit,  British,  170. 
Thermostat,  White,  549. 
Thiem  motor  cycle,  des.  and  ills.,  459. 
Thorneycroft,  Sir  John  Isaac,  40. 

water  tube  boiler,  ills.,  490. 
Thread  tires,  109,  110. 

manufacture  of,  112. 
Three  cylinder  engine,  329. 
Three  point  support,  advantage  of,  68. 

suspended  spring,  ills.,  70. 
Three  speed  selective  transmission,  diagram. 

372. 

Three-wheel  carriage,  advantage  of,  68,  69. 
Throttle  adjustment,  426. 

after  starting,  431. 
Throttle,  control,  623. 

governors,  340,  353. 

levers,  611. 

valves,  239. 
Throttling  device,  Mora,  346. 


INDEX 


665 


Throttling  fuel  mixture,  349. 
Through  axle  shaft  and  liner  tube,  22. 
Tickler  of  carburetter,  215. 
Tiller  and  wheel  steering,  65. 
Tiller  steering,  58. 

danger  of,  65. 
Tillinghast,  P.  W.,  110-111. 

tire,  110-111. 
Time,  correct  for  ignition,  350. 

element  in  power  estimates,  201. 

of  ignition,  157. 
Timer,  rotor,  287. 
Timers,  281,  286,  287,  288,  318. 

stationary  part,  287. 
Timing,  336,  337,  338,  339. 

automatic,  352. 

device,  defects  in,  438. 

device,  failure  to  start,  432. 

of  ignition,  340. 

valve  and  spark,  des.  and  ills.,  461. 
Tires,  Dunlop,  117. 

Fisk,  117. 

for  steam  truck,  ills.,  101. 

Goodyear,  117. 

leather  reinforced,  120. 

nipping  of  air  tube,  120. 

pressures,  126. 

side  flange,  117. 

valves,  118. 

Tires  and  road  surfaces,  100. 
Tires,  care  of,  125. 

chemical  action,  124,  125. 

cleaning  of,  641. 

clincher,  ills.,  116. 

comparison  of,  113. 

cracking,  122. 

creeping  of,  119,  120. 

dampness,  125. 

dimensions,  126. 
Tires,  double  tube,  108-109. 

advantages,  115. 
Tires,  excessive  wear,  122-124. 

fabric,  109. 

method  of  attachment,  ills.,  112,  113. 
s,  pneumatic,  102,  107-131. 

absorb  vibration,  75,  77. 

advantages  of,  107-108. 

care  of,  125-128. 

chemical  action,  124,  125. 

cracking,  122. 

creeping,  119,  120. 

dampness,  125. 

dimensions,  126. 

excessive  wear,  122-124. 

mishaps,  ills.,  130. 


Tires — Continued. 

necessity  for,  1. 

pressure,  126. 

puncture  of,  120. 

puncture,  120. 

repair  of,  128,  129. 

removal  from  wheel,  127-131. 

repair  of,  128. 

rim-cutting,  121,  122. 

rubber,  first  use  of,  11. 

rubber,  solid,  99-118. 

single  tube,  108-109,  113. 

single  or  double,  comparison,  113-114. 

troubles  with,  119-125. 
Tires,  solid,  102-106. 

durability,  104. 

method  of  attachment,  ills.,  103. 

structural  requirements,  104. 
Tires,  thread,  109. 

single  tube,  110. 

manufacture  of,  112. 
Toledo  engine,  349. 

transmission  gear,  357. 
Tool  kit,  643. 

Torque  of  steam  engine,  468. 
Transmission  Brush  planetary,  des.  and  ills., 
390,  391. 

Cannstadt-Daimler,  382,  383. 

care  of,  638. 

Columbia,  ills.,  384-386. 

DecauviUe,  384,  385. 

Decauville,  ills.,  368,  369. 

friction  disc,  361,  362. 

Haynes-Apperson,  ills.,  388,  390. 

Knox-Mercedes,  ills.,  386,  387. 

motor  cycle,  463,  464. 

necessity  for,  367. 

Pope-Toledo,  ills.,  380. 

progressive,  370,  616. 

selective  spur  type,  381,  616. 

types  of,  370. 

Whinton,  393. 
Transmission  gear,  forms,  357. 

ratios,  393. 

Transmission  gears,  various  positions  of,  373. 
Transmission  lever,  615. 
Transmission  principles,  diagram,  369. 
Transmissions,  367-393. 

selective,  372. 
Traveling  nut,  59. 

and  rack,  61. 

Trevithick's  steam  carriage,  ills.,  3,  4. 
Trolley  lines,  631' 
Troubles,  electric  motor,  568. 

ignition,  315-322. 


666 


IXDEX 


Troubles— Continued. 

with  large  wheels,  97. 
Try  cocks,  516.  518 
Trucks,  electric,  656. 
Truffault  spring  suspension,  86. 
Tube  expander,  ills.,  487. 
Tubes  for  boilers,  489. 
Tubular  boilers  in  general,  487. 
Turning,  arc  of  railroad  wheels,  46. 

corners,  diagrams,  630. 

in  a  street,  diagram,  631. 
Two-cycle  gas  engine,  158-162. 

advantages,  159. 

diagram,  159,  160. 

disadvantages,  160. 

essentials  of ,  159.  160. 

exhaust  of,  160,  161,  162. 

for  motor  vehicles,  158. 

governing,  162. 

operation  of,  158. 
Types  of  transmissions.  370. 

u 

Ultimate  load,  76. 
Underframes,  advantages  of,  67. 

early  forms,  67. 

Units  of  electrical  measurements,  560. 
Universal  joint,  differential,  ills.,  22. 
Unusual  driving  devices,  63. 
Unusual  steering  devices,  63. 


Vallee,  356. 

Value,  calorific,  of  fuels,  199. 

Valve,  by-pass,  operating,  514. 

cam,  diagrams,  338. 

generator,  246. 

gear,  four-cycle,  ills.,  441. 

lift,  Peugeot,  342. 

lift,  variable,  342,  345. 

lift,  regulation,  340. 

opening,  how  to  calculate,  235. 

springs,  152. 

timing,  ills.,  461. 

vaporizer,  ills.,  246. 
Valves,  automatic  inlet,  151,  152.  • 

by-pass,  513. 

grinding,  ills.,  425. 

grinding  with  screw  driver,  ills.,  425. 

method   of   grinding   in   horizontal   cyl- 
inders, 424. 

mushroom,  151. 

poppet,  151. 

positive  inlet,  151,  152. 


Valves — Continued. 

simpling,  of  White  engine,  ills.,  483 

throttle,  239. 

tire,  118. 
Vaporization,  due  to  heat,  226. 

due  to  pressure,  226. 
Vaporizer,  function  of,  205-206. 

valve,  ills.,  246. 
Variable  stroke  gas  engine,  180. 

valve  lift,  342,  345. 
Variation  of  fuel  mixture,  340. 
Varieties  of  carburetter,  206. 
Varying  mixture,  347. 

point  of  ignition,  350. 

volume,  347. 

Vegetable  oils,  why  avoided,  412. 
Vehicle  engine,  essential  parts,  152,  153. 
Vehicles,  light  electric,  556.  • 
Venturi  carburetter,  230-232. 

principle,  231. 

Verdigris,  should  be  removed,  263. 
Vibration,  318. 

absorption  of,  85. 

necessary  to  absorb,  85. 

reduction  of,  99. 
Vibrator,  adjustment  of,  435 

adjustment,  faulty,  436. 

coil,  281-285. 

coil,  diagram,  282. 

coil  ignition,  300. 

coils,  297. 

failures,  433-435. 

hammer,  285. 

plain,  284. 

Vinot  steering  wheel,  423. 
Volatile  fuels,  advantages  of  using,  503. 
Voltage,  255. 

Voltaic  induction,  action  of,  diagram,  560. 
Volt-ammeter,  index  scales,  diagram,  563. 

forms  of,  563. 
Voltmeter,  diagram,  562. 

indications,  564. 
Volts,  255. 
Volume,  final.  163-164. 

gas,  law  of,  137-140. 

initial,  163-164. 

throttling  device,  More,  346. 

varying,  347. 

w 

Walker  semi-flash  boiler,  495. 

illi.,  494. 
Water,  acid  should  be  added  to,  261. 

column,  ills.,  518. 

connections,  Lane,  534. 


INDEX 


667 


Water — Continued , 

connections,  Stanley,  527. 

cooling  for  cylinders,  183-190. 

gauges,  518. 

gauges,  ills.,  518. 

glass,  516,  517. 

glass  troubles,  518. 

in  carburetter,  445. 

indicator.  Lane,  534,  535 

indicator,  ills.,  534. 

jacket,  efficiency  of,  184. 

jacket,  freezing,  424. 

level,  Stanley,  529,  530.  531. 

level,  Stanley,  ills.,  529. 

regulator,  Ofeldt,  ills.,  516. 

straining,  418. 

tank,  Lane,  534. 

tube  boilers,  491. 

water  tube  boilers,  advantages  of,  491. 

weight  of,  165. 
Waverly  motor  generator  charging  set,   ills., 

587. 
Weak  battery,  260,  261,  440. 

explosions,  251. 
Wear  in  tires,  119. 
Welch  valve,  ills.,  118. 
Western  volt-ammeter,  ills.,  565. 
Wheel  base,  51. 

and  center  of  gravity,  51. 

long,  why  important,  56,  57. 
Wheel  steering,  advantages  over  tiller,  58. 

how  to  hold  wheel,  66. 

principles  of,  65. 
\Vheels,  artillery  construction  of,  89-90. 

artillery,  ills.,  91-93. 

dimensions  of,  95. 

dishing  of,  52,  92-94. 

Hancock,  92. 

motor  carriage,  89-98. 

railroad,  position  in  turning  curve,  48. 

relative  merits  of  large  and    small,    96, 
97,  98. 

requirements  for,  89. 

spring,  12. 

steel  tubular,  advantages,  90,  91. 

steering,  47. 

wire,  faults  of,  90. 

wooden,  merits  of,  91,  92,  94-95. 


White,  boiler  tests,  554. 

burner  and  connections,  511. 

car,  ills.,  550,  551. 

car  operation,  551,  552,  553. 

car  starting,  550. 

compound  engine  ills.,  483. 

diagram,  544. 

diagram  of  water  circulation  501. 

engine  valves,  ills.,  483. 

flash  generator,  500. 

flash  steam  generation,  544,  545. 

flow  motor,  547,  548. 

on  steam  vehicles,  133. 

regulating  requirements,  543. 

steam  generator  and  burner,  ills.,  511. 

steam  system,  543. 

system,  524. 

thermostat,  ills.,  549. 

water  regulator,  des.  and  ills.,  546,  547. 
Willet  carburetter,  233. 
Winding,  primary,  257. 

secondary,  257. 
Winton,  342,  343. 

carburetter,  ills.,  219. 

clutch  and  transmission,  393. 

dash  assemblage,  619. 

lubrication  system,  420. 

pneumatic  control,  340. 

pneumatic  governor,  343,  344. 

self  starter,  619. 

six-cylinder  engine,  328. 

springs,  ills.,  85. 

transmission  gear,  357. 
Wire  for  battery  connection,  260. 

wheels,  faults  of,  90. 
Wiring,  break  in,  316. 

diagram  of  four-cylinder  car,  321. 

incorrect,  diagram,  260. 
Wooden  artillery  wheels,  91. 

wheels,  merits  of,  94-95. 
Wood  valve,  ills.,  118. 
Wood  wheel,  92. 
Words  of  caution,  644. 
Working  strength  of  springs,  79. 

unit,  100. 

Worm  and  sector  steering  gear,  60. 
Wrench,  large  on  small  nut,  ills.,  415. 

use  of,  ills.,  415. 


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Electric    Lighting.    Wiring;     The     rules     and 
requirements' 

Electrical  Measurements;  Telephone  and  Telegraph  Instruments; 
The  Electric  Railway:  Line  Work;  Instructions  and  Cautions 
for  Linemen  and  Dynamo  Room:  Storage  Batteries:  Care  and 
Management  of  the  Street-Car  Motor;  Electro  Plating. 

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Price    <j}2    Postpaid. 


NEW 
CATECHIS 

OF  THE  I 

STEAM  ENGINE! 


STEAM  ENGINE   RUNNING,  $2 

A  Valuable  Treatise  on  all  Types  of  Engines,  in- 
cluding Care,   Management  and  Repairing. 

WHEN  an  engine  has  been  com- 
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work  of  several  men  to  be  ex- 
pended in  its  care  and  management. 
All  steam  engineering  literature  is  full 
of  the  subject  of  economy  in  operating 
the  machine;  the  author  desires  to  aid 
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life  work  and  well    being  of  his  special 

patrons,  the  engineers  in  charge  of  the 
steam  plants. 

"It  has  been  well  said  that  engineers 
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A  partial  list  of  subjects,  which  are 
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Personal  Introduction.  The  Steam 
Engine.  Historical  Facts  Relating  to 
the  Steam  Engine.  Engine  Founda- 
tions. The  Steam  Piston.  Connecting 
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and  Gas  .Engines. 

_This  is  a  rarely  fine  book,  handsomely  bound  in  green  silk  cloth, 
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Price    CJ2    Postpaid. 


AUDELS     ANSWERS     ON 

Practical  Engineering 

When  yoti  spend  your  good  hard  earned  money  for  books,  always 
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'T'HIS  book  deals  largely 
•*•  with  the  foundation  prin- 
ciples which  govern  the  prac- 
tice of  steam  engineering. 
Nothing  so  soon  condemns 
the  applicant  as  want  of 
knowledge  of  the  every  day 
practice  and  simple  laws  relat- 
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ment of  a  steam  plant. 

No  one  is  expected  to  know 
everything,  but  allare  required 
to  be  familiar  with  certain 
facts  which  may  be  called  "the 
beginning  of  things." 

The  lack  of  knowledge  of 
the  small  things  carries  con- 
viction of  the  same  lack  in 
the  larger. 

Plain  facts,  that  you  should 
know,  are  plainly  explained  in 
AUDELS  ANSWERS  ON  PRAC- 
TICAL ENGINEERING, 

answering  your  questions  on 

AIR,  WATER,  STEAM,  FUEL 
AND  HEAT,  STEAM  BOILERS, 
BOILER    CONSTRUCTION, 
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AGEMENT OF   BOILERS,    ENGINEERS- 
LAW,  FIREMEN'S  LAW,  STEAM  ENGINES, 
THE  VALVE  AND  VALVE   GEAR,  THE  CORLISS 
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PUMPS,   INJECTORS,    FEED   WATER   HEATERS,  STEAM 
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LEARN  THE 'THEORY  UNDERLYING  THE  WORK. 

Practical  Engineering  contains  288  pages  fully  illustrated,  hand- 
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PRICE    POSTPAID    TO   ANY   ADDRESS, 
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THEO.  AUDEL  &  CO.,  Publishers, 

72    FIFTH    AVENUE.  NEW   YORK 


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UCSB   LIBRARY 


UC  SOUTHERN  REGIONAL  LIBRARY  FACILITY 


A    000655618     7 


